Search Investigations
searchinvestigations.org
Confidential — Law Enforcement Sensitive
Chelsea Grimm, age 32 at the time of disappearance, was a social worker and photographer from San Diego, California. She was last confirmed seen on September 30, 2023 in the Kaibab National Forest area west of Williams, Arizona, within Coconino County. Her vehicle, a white Ford SUV (CA plate 8TDG491), was found abandoned on FSR 6 on October 5, 2023 — out of gas with two blown tires, doors locked, with her camera and iPhone SE (SIM card previously removed) left inside.
Chelsea departed the vehicle on foot carrying a tarp, backpack, approximately one gallon of water, an AAA Arizona almanac, her bank cards, and a Hare Krishna book titled "Chant and Be Happy." A blue shelter was subsequently spotted by drone on a ridgeline above MK Tank, approximately 2.19 miles south of where her car was found. The color matches a blue shelter visible inside Chelsea's backpack in her Instagram story photo, which is the basis for believing this is Chelsea's camp — though this has not been confirmed. Since September 30, 2023, there has been zero credit card activity, zero bank activity, and zero social media engagement.
Chelsea had completed the Anasazi Foundation wilderness survival program — a 49-day primitive skills course covering fire-making, shelter construction, navigation, and foraging. At the time of disappearance, she was exhibiting signs of religious/spiritual psychosis, including syncretic beliefs, ritualistic behavior, and systematic disconnection from all electronic tracking over a 3-day period. She refused help from four separate individuals on her final day of confirmed contact.
Assessment: Based on the totality of evidence reviewed — including her laptop, phone, social media accounts, behavioral patterns, Dollar General receipt, and a potential sighting of her blue shelter by drone — we believe Chelsea is in the forest. We have no evidence to suggest otherwise.
Search Investigations' cumulative effort since December 2025 now totals 14 field days across multiple operations plus ongoing drone image analysis. The day-by-day breakdown below is the 3/27/26 – 4/2/26 operation (5 field days + 1 analysis day); cumulative totals across all operations are summarized in the table that follows. All search areas were defined using the Lost Person Behavior model (Robert Koester, International Search & Rescue Incident Database / U.S. Department of Justice), CalTopo terrain analysis, and evidence-based behavioral profiling of the subject.
Deployed ground teams to the primary search area centered on the blue shelter sighting location above MK Tank (35.37961, -112.38696). Conducted initial reconnaissance of the ridge where a blue shelter/tarp believed to be Chelsea's was spotted by drone (matching the blue shelter visible in Chelsea's backpack in her Instagram story). Covered surrounding terrain on foot, documented conditions, and began establishing search grid and GPS tracking for systematic coverage.
Tracks logged: 10 ground tracks recorded to CalTopo.
Expanded search coverage across the full ridge system and surrounding terrain. Deployed DJI M30T drone for aerial survey operations, capturing high-resolution still imagery and video at multiple altitude profiles. Began systematic documentation of terrain features, water sources, and potential travel corridors from the shelter location.
Tracks logged: 11 ground tracks. Initial drone imagery collected.
Dedicated analysis day focused on reviewing all collected drone imagery, formulating the next phase search strategy based on terrain analysis, coverage gaps, and behavioral modeling. Cross-referenced drone footage with CalTopo mapping data to identify priority areas for the following search days.
Executed targeted search pattern based on Day 3 analysis. Ground teams covered washes and descending ridgelines south of the shelter location. Continued drone survey flights at varying altitudes to capture additional coverage areas. Covered the entire ridge and surrounding areas. While no physical remnants were located, the team identified the exact rock where Chelsea had been sitting based on the drone imagery alignment. From this vantage point, her full line of sight was documented — an approximately 180-degree view of the surrounding terrain.
Tracks logged: 12 ground tracks + 4 drone flights recorded.
Key observation: The position she chose offered a wide, commanding view of the terrain — a very intentional and tactical choice. From that vantage point, she would have been able to clearly see search and rescue crews operating in the area. This is consistent with her Anasazi training (selecting elevated positions with visibility) and her pattern of avoiding detection and refusing help.
Flew structured drone patterns at approximately 400 ft AGL, moving at higher speeds while capturing rapid high-resolution imagery over a significantly expanded search radius. Knowing the exact color of Chelsea's tarp (teal/blue-green), this method allowed efficient scanning of a much broader area within a 2–3 hour operational window. Ground teams began moving downward from the ridge, covering the wash system and descending ridgelines. This area branches into three separate paths, creating a wide zone with multiple potential routes.
Tracks logged: 14 ground tracks + 2 drone survey flights. Thousands of high-resolution still images captured.
Continued ground search operations expanding coverage southward along identified travel corridors. Additional drone flights targeting remaining coverage gaps. All imagery collected for ADIAT color detection processing.
Tracks logged: 15 ground tracks + 1 drone flight recorded.
| Metric | Count | Notes |
|---|---|---|
| Total Ground Tracks | 259 | Logged via CalTopo across all operations (Dec 2025 – Apr 2026) |
| Search Days | 14 | Cumulative field days across all operations (Dec 2025 – Apr 2026) |
| Drone Flights | 18+ | DJI M30T, multiple altitude profiles (67m – 400ft AGL) |
| High-Res Still Images | 84,000 | Captured cumulatively across all drone flights for analysis |
| Video Files | 100+ | Terrain documentation, flyovers, targeted surveys |
| Map Markers | 251 | Waypoints, evidence, structures, water sources, anomalies |
| Homes/Structures Mapped | 160+ | All structures within search radius documented |
| ATV Search Tracks | 4 | Extended range reconnaissance on forest roads |
| Water Tanks Checked | 6 | MK, Frenchman, Paradise, Mesa, Toughy, Elk |
ADIAT (Autonomous Detection of Items in Aerial/Terrestrial imagery) is an AI-powered detection system that scans drone imagery for specific color signatures using a Matched Filter algorithm. For this case, the system was configured to detect the exact hex color of Chelsea's tarp/shelter:
Status: Initial run completed on April 1 batch. Detected 2 areas of interest with confidence scores of 50.8% and 41.7%. All 84,000 cumulative drone images (since Dec 2025) are currently being processed through ADIAT for comprehensive color detection across the full search area.
Detection example: The system flagged a small teal/cyan object partially obscured by tree canopy at coordinates 35.3637, -112.3738 — demonstrating its capability to isolate color-matched items within dense vegetation from drone altitude. Note: this same coordinate is the “Under Review” ADIAT hit documented in Key Findings below; the object has not yet been ground-verified.
All 84,000 high-resolution still images and 100+ videos (cumulative since Dec 2025) have been processed through Eagle Eye, an anomaly detection platform that identifies visual irregularities in aerial and ground-level imagery. The system flags potential items of interest including:
Status: Initial review pass complete. All flagged anomalies are being cross-referenced with ADIAT color detection results. Imagery will be double-reviewed with both systems to ensure no items of interest are missed.
All search operations are mapped and tracked in real-time via CalTopo (caltopo.com/m/365UJR6). The map includes:
Primary aerial platform for search operations. Capabilities deployed:
All search areas were defined using the Lost Person Behavior framework established by Robert Koester and published through the International Search & Rescue Incident Database (ISRID), referenced by the U.S. Department of Justice. This model is the industry standard used by virtually every organized search and rescue team in the United States and provides statistically validated probability zones based on subject category, terrain, and environmental factors.
Chelsea's profile was classified as follows under standard Koester / ISRID LPB framework:
Key parameters from the model that shaped our search strategy:
A blue shelter / teal tarp was spotted by drone on a ridgeline directly above MK Tank at 35.37961, -112.38696 — matching the blue shelter visible in Chelsea's backpack in her Instagram story. This is 2.19 miles south of her vehicle on a bearing of 158°, consistent with her southward on-foot movement pattern. While this has not been confirmed as Chelsea's, the camp location is consistent with Anasazi site selection training: elevated position on a ridge 580 feet directly above a full water source.
During Day 4 operations, the team identified the exact rock where a person had been sitting, verified through alignment with earlier drone imagery of the blue shelter sighting. From this vantage point, the team documented her complete ~180-degree line of sight over the surrounding terrain.
Critical implication: From this position, Chelsea would have had clear visual contact with any search and rescue activity in the area. Her choice of this position — combined with her pattern of refusing help from every person she encountered — strongly suggests she was actively avoiding detection. This is consistent with both her Anasazi ridge-position training and her deliberate disconnection behavior.
The ADIAT system flagged two consecutive drone images from the April 1 flight showing a color-matched object in vegetation approximately 1.1 miles SSE of the shelter location:
| Image | GPS (Est. Ground) | Confidence | Color Match | AGL |
|---|---|---|---|---|
| DJI_20260401133146_0343 | 35.363653, -112.373804 | 50.8% | Hue 170° #00ffd7 | 67.4m |
| DJI_20260401133149_0344 | 35.363554, -112.374109 | 41.7% | Hue 185° #00e7ff | 66.4m |
Both images show a small teal/cyan object partially obscured by tree canopy. The detection location falls on the "Possible Path Taken" route (SSE from the shelter) and is within the Priority 1 search corridor. This location requires ground verification.
The shelter sighting is directly above MK Tank, which was confirmed full at the time. With approximately 1 gallon of water capacity, Chelsea had roughly one day of hydration in October Arizona conditions (highs 60s, lows 30s °F). She would need to locate a new water source within approximately 1 day of departure or face dehydration. At a sustainable wilderness walking pace, this constrains her effective travel radius from MK Tank to roughly 6–10 miles before a required resupply.
| Water Source | Distance from Shelter | Search Tracks (0.5mi) | Status |
|---|---|---|---|
| MK Tank | 0.11 mi (580 ft) | — | PRIMARY — confirmed full |
| Frenchman Tank | 1.02 mi E | 26 | Well covered |
| Paradise Tanks | 2.13 mi NW | 13 | Moderate coverage |
| Mesa Tank | 2.46 mi E | 2 | BARELY SEARCHED |
| Toughy Tank | 2.52 mi NE | 5 | Light coverage |
| Elk Tank | 3.46 mi NE | 0 | ZERO COVERAGE |
Additional research uncovered accounts from a former Anasazi Foundation counselor describing how participants were trained to sustain themselves with nutrient-dense supplies such as Gatorade powder, salt, and baking soda to prevent dehydration. This directly aligns with Chelsea's Dollar General receipt, which included salt and baking soda, suggesting she was actively applying wilderness survival skills learned during her time at the program.
Additional behavioral parallels identified:
Reference: Former counselor account (Reddit)
A comprehensive review of Chelsea's digital footprint was conducted covering her laptop, phone, social media accounts, and financial records. The following summarizes the findings from each channel.
Chelsea was carrying two Apple devices:
KEY FINDING — iPhone X physically activated 7.5 months after disappearance. Apple's iOS Device Activation logs for the iPhone X show a 37-minute window on 2024-05-17 (20:42:51–21:20:08 UTC) with 200 unique activation events — 274 distinct IMSIs (all sharing MSIN suffix …73956326), 2 unknown foreign ICCIDs, source IPs in Canada and the United Kingdom, and Apple SIM policy code CYPRESS. CCSO Det. Cody Watson met with an Apple software engineer in person on 2025-08-04 who confirmed the physical device had been activated — not an IMEI clone.
The iPhone X has no eSIM — a physical nano-SIM is required — meaning someone with hands-on possession of the device inserted a SIM. The leading interpretation is a multi-IMSI travel SIM. Updated carrier identification (2026-04-11): the US carrier is T-Mobile US (IMSI prefix 310260), and the foreign carrier is A1 Slovenia.
Subscriber identification efforts to date:
NEW LEAD (2026-04): Search Investigations has contacted the Arizona Game & Fish director requesting a cross-reference of European nationals who obtained Arizona hunting tags in the 2023–2024 seasons in GMU-10 (Kaibab NF) and adjacent units, on the theory that a European visitor to the search area may have found the phone. Awaiting director's response.
Interpretation: the iPhone X is believed to be in someone else's possession, found in the forest, and being provisioned through a multi-IMSI rotation with European / UK / Canadian endpoints. Identifying the subscriber behind the foreign ICCIDs remains the single most promising lead for locating Chelsea.
Chelsea's laptop and social media accounts were reviewed for behavioral indicators and intent signals. Key findings:
In the month leading up to her disappearance, Chelsea reposted several quotes, images, and videos referencing survival themes and a desire to be alone in the wilderness. Examples include:
Social media screenshots and additional posts are documented in the case file for reference.
Search Investigations has reached out to the Coconino County Sheriff's Department to request helicopter footage from the ridge area where a drone sighting of a shelter (and possibly a figure) was recorded. Corroboration is needed because this sighting is not confirmed to be Chelsea. Helicopter footage from the 2023-10-06/07 initial SAR would help verify whether the shelter/figure was present during the earlier search. As of this report date, we have not received a response.
Major gap at 2.5–3.0 miles: Only 34% coverage at this critical distance band. This zone falls along Chelsea's probable southward travel corridor and includes the transition from searched to unsearched terrain. Coverage beyond 3 miles is minimal to nonexistent.
| Direction | Gap Size | Distance | Center Point | Priority |
|---|---|---|---|---|
| South | 12+ cells | 0.8 – 2.0 mi | 35.358, -112.387 | P1 |
| South | 14 cells | 2.5 – 3.0 mi | 35.344, -112.387 | P1 |
| East | 23 cells | 2.0 – 3.0 mi | 35.379, -112.342 | P2 |
| West | 20 cells | 2.0 – 3.0 mi | 35.379, -112.431 | P3 |
| Southwest | 6 cells | 0.9 – 1.8 mi | 35.362, -112.398 | P2 |
The following areas have been thoroughly covered through combined ground and aerial search operations:
Every confirmed on-foot movement by Chelsea trends south to southwest:
| Segment | Distance | Bearing | Direction |
|---|---|---|---|
| Camp → Meadow (G&F encounter) | 0.98 mi | 222° | SW |
| PLS (vehicle) → Shelter | 2.19 mi | 158° | S |
| Average on-foot bearing | 190° | S | |
She told the Arizona Game & Fish officer she intended to go "north" but actually traveled south. She was either intentionally misdirecting or her plans changed. Either way, her actual movement was consistently southward.
This was not an impulsive act. Over several days, Chelsea executed a systematic plan:
Most probable: South to SSW (bearing 160–200°)
Supporting evidence for south:
Secondary possibility — ESE toward "Humphreys" (Humphreys Peak, ~45 mi): She told the Worthingtons this was her destination, and the mountain holds spiritual significance. However, 45 miles with a tarp and 1 gallon of water would be nearly impossible.
Search Investigations has contacted the Arizona Game & Fish director requesting a cross-reference of European nationals (or persons of European origin) who obtained Arizona hunting tags in the 2023 and 2024 hunting seasons in Game Management Unit 10 (GMU-10, Kaibab NF) and adjacent units. Goal: identify potential finder(s) of Chelsea's iPhone X.
Rationale: The 2024-05-17 Apple activation event showed foreign ICCIDs and source IPs in Canada and the United Kingdom. EU privacy regulations have blocked IMEI-based device-tracking software from returning data on the foreign SIMs. A European hunter with physical access to the Kaibab search area is a plausible finder of a phone abandoned after Chelsea's disappearance. Status: Awaiting director's response.
All 84,000 drone images (cumulative since Dec 2025) are currently being run through ADIAT for color detection matching the exact hex code of Chelsea's tarp. The initial run has already flagged two areas of interest at 35.3637, -112.3738 (1.1 mi SSE of the shelter). These detections — and any additional flags from the full processing run — require ground verification by a search team to confirm or rule out.
The 34% coverage zone at 2.5–3.0 miles on Chelsea's primary bearing is the most critical unsearched area. This corridor (35.340–35.370 lat, -112.410 to -112.360 lon) includes the CG-31 and CG-30 search segments at 3.4–3.7 miles south. With 1 gallon of water, she could reach approximately 5 miles before a dehydration crisis. Search drainages, ridgelines, and terrain traps.
The mapped egress route running SSW from the shelter ends at 4 miles. The drainage continues south toward I-40 (8.6 mi total). Walk the drainage channel from mile 4 to mile 7, checking both banks and side channels within 0.25 miles. Our best estimate places Chelsea approximately 6 miles SSW of the shelter (35.2960, -112.4180), along this drainage.
All drone footage (84,000 stills, 100+ videos cumulative since Dec 2025) to be reviewed through both Eagle Eye anomaly detection and ADIAT color detection. This dual-system approach ensures maximum probability of identifying items of interest that may have been missed in single-pass manual review.
If Chelsea angled east toward "Humphreys," Mesa Tank (2.46 mi E, only 2 search tracks) and Elk Tank (3.46 mi NE, zero coverage) are the first water sources on that route. Search 1-mile radius around each tank plus the connecting corridor between them.
The 97-page CCSO Grimm Report 2025-10-24 records several material developments not previously reflected in this report:
| Date/Time | Event | Location |
|---|---|---|
| Sep 27, 3:06 PM | Disables FindMy on iPhone leaving Phoenix | — |
| Sep 27, 3:40 PM | Final cell ping | Whitman, AZ (60 & 203rd) |
| Sep 28, 8:00 PM | Williams PD encounter at cemetery (bodycam) | Williams, AZ |
| Sep 28, 8:32 PM | Drives onto Worthington property, says "Humphreys" | 35.251, -112.236 |
| Sep 28 | Tries to check into motel, pays with euros, denied | Unknown motel |
| Sep 29, 6:36 AM | Parked off FR 124 | 35.308, -112.338 |
| Sep 29, 10:18 AM | Live photo at FR124/FR6 junction — "I do have to leave you here" | 35.314, -112.355 |
| Sep 29, 12:09 PM | Arrives at camp location via FR 6 (drove north) | 35.393, -112.357 |
| Sep 29, 6:00 PM | Films campsite video | 35.394, -112.353 |
| Sep 27 | Removes SIM card from iPhone (same day Find My disabled, phone goes dark 3:40 PM) | — |
| Sep 30, 7:54 AM | Still at camp, car visible in photo | 35.394, -112.353 |
| Sep 30, 9:06 AM | Photos of clothes hanging in tree (exit route) | 35.393, -112.357 |
| Sep 30, 11:00 AM | Game & Fish officer encounter in meadow. Says "walk out, north" | 35.382, -112.368 |
| Sep 30, 1:00 PM | Seen with vehicle at PLS / final car location | 35.409, -112.401 |
| Sep 30, 5:08 PM | White truck driving erratically at Paradise Tanks | 35.394, -112.422 |
| Sep 30, 5:52 PM | FINAL PHOTO at car location | 35.409, -112.401 |
| Sep 30, ~6:00–11:45 PM | Departs vehicle on foot. Bearded dragon photographed deceased at vehicle (cause unconfirmed); writes note, locks car. | PLS |
| Sep 30, 11:45 PM | Hunting guide drives by — car present, Chelsea gone | PLS |
| Oct 5, 7:56 PM | Tasha Howard calls in abandoned vehicle | PLS |
| Oct 6, 7:00 AM | SAR responds to vehicle location | PLS |
| Oct 6, 11:00 AM | Jay Bigwood finds clothes in tree at camp | 35.393, -112.357 |
| Oct 20, 2023 | Blue shelter drone-spotted on ridge above MK Tank — believed to be Chelsea (NOT confirmed). 20 days after last contact. | 35.37961, -112.38696 |