Key facts
- Name: Hoi Kei “Patricia” Woo
- Born: Hong Kong (exact date not publicly confirmed; age 35 in 2025)
- Age at disappearance: 35
- Last seen: April 18, 2025
- Location: Last seen in Tucson, Arizona; her car was found April 20, 2025, at Windy Point Vista on Mount Lemmon (Catalina Highway), Pima County
- Height / build: 5’4″, 100–125 lbs; brown hair, brown eyes; wears glasses; last seen wearing a black shirt and pajama pants
- Status: Still missing — Pima County Sheriff’s Department search “exhausted all resources”; family offering $5,000 reward
- Case numbers: Not publicly confirmed
- Investigating agency: Pima County Sheriff’s Department — (520) 351-4900
The car on the mountain
On April 18, 2025, Hoi Kei “Patricia” Woo left the Tucson home she shared with her husband, Zhou “John” Zheng, and never returned.
Two days later, a friend found her car — a white Volkswagen, license plate FRA6AR — at Windy Point Vista on Mount Lemmon, the scenic overlook high above Tucson on the Catalina Highway. Locked inside: her phone, her purse, and her walking stick.
Patricia was, by every account, a city girl. “I don’t think of her as a hiker,” her friend Thomas said. “She’s a city girl. She would not have gone out [in public] like that.” What she was last seen wearing — a black shirt and pajama pants — struck everyone who knew her as wrong. “I’ve never seen her go out in public in pajama pants,” Thomas said.
Even stranger: the phone. “She’s a person [who] always responded within like an hour of you messaging her. And if you called her, she usually picked up,” Thomas said. “She took millions of pictures. Like she filled up her phone. I don’t think she would just leave her phone there.”
A woman who never went anywhere without her phone left it locked in a car on a mountain she didn’t hike, dressed in clothes she didn’t wear in public. That is the shape of this mystery.
Who Patricia was
Patricia Woo was a native of Hong Kong who came to the United States on a student visa. Her first encounter with the University of Arizona came during an exchange program while she was earning her bachelor’s degree in Hong Kong. She stayed — graduating in 2024 from the UA’s Eller College of Management with a master’s in business analytics, and telling the school’s student profile that she hoped to work in artificial intelligence.
Friends describe her as outgoing, intelligent, deeply cherished — “a bright light,” in her family’s words. In the spring of 2025, she was looking for a job, meeting with people about a research position. Thomas had been planning to visit Tucson that very week she disappeared. “She was looking for a job [and] she was meeting with people to find a research position,” he said. “She had plans for the future.”
Her friend Hunter had a meeting set with her for the following Monday at 1 p.m. “I was kind of desperately waiting for that meeting and just kind of hoping some sort of miracle is going to occur and she’ll pop on it at 1 p.m.,” he said. “Unfortunately, that did not happen.”
She had also, according to those close to her, been in deep distress about her standing with her student visa.
Two weeks after she was reported missing, friends and professors held a candlelight vigil in the Eller College’s McClelland Auditorium — a few dozen people sharing stories about Patricia and hoping for her safe return. “It almost sounds cliché, but it’s so abundantly true — being around her and seeing the candlelight vigil was just further confirmation that she inspires care in the people around her,” said her labmate Gaiser.
The search that ran out of mountain
The Pima County Sheriff’s Department threw everything it had at the first days: the Arizona Department of Public Safety, Tucson Police, the U.S. Forest Service, U.S. Border Patrol, and the Southern Arizona Rescue Association. Scent dogs, drones, foot searches of the Windy Point area. Nothing — no scent, no clothing, no sign.
Six days after she was declared a missing person, PCSD released a statement saying it had “exhausted all resources” and moved the case to limited continuous mode: new tips would be investigated, and active searching would resume if necessary. Days later, deputies and rescue volunteers were spotted with a large drone filming over the cliff off Windy Vista Point.
Her parents — retired, living in Hong Kong — have been supporting the search from across the world. The family launched a GoFundMe to hire a private investigator and keep the effort going, and is offering a $5,000 reward. The 857Tucson channel and crime correspondent Joe Schmoe have kept the case in front of the public with timeline reconstructions and appeals for dashcam and drone footage from Mount Lemmon over Easter weekend 2025.
Theories: what might have happened
Suicide. The facts that point here: the car at a scenic overlook, the phone and purse deliberately left behind, the pajama pants — the clothes of someone not planning to come back — and the reported distress over her visa standing. The cliffs below Windy Point are unforgiving, and days of searching with dogs and drones found nothing, which is consistent with a fall into terrain that swallows evidence. What must be said: this is an inference from circumstances, not a finding. Her friends insist she had plans for the future — a job search, a Monday meeting — and people with plans also die by suicide. But no note, no witness, and no remains have confirmed anything.
Foul play. Her husband is the person who last shared a home with her, and in any missing-spouse case the spouse is looked at first. What is known publicly: nothing has been announced implicating anyone, and speculation about any individual would be irresponsible. The presumption of innocence applies fully. What keeps the question open is simply how little is confirmed about the hours between Patricia leaving home and her car appearing on the mountain.
A mental-health crisis that ended in the desert. Between the two poles — intent and violence — lies the possibility that a distressed woman drove up the mountain in crisis and wandered into country that killed her without leaving a recoverable trace. The walking stick locked in the car argues against a planned hike; the pajama pants argue against any plan at all.
Have information?
Contact the Pima County Sheriff’s Department at (520) 351-4900 or dial 911. The family is offering a $5,000 reward. Anyone with video, dashcam, or drone footage of Mount Lemmon over Easter weekend 2025 (April 18–20) is urged to review it and send it in.
Timeline
- 2024 — Patricia Woo graduates from the University of Arizona’s Eller College of Management (MSBA); hopes to work in artificial intelligence.
- April 18, 2025 — Patricia leaves the Tucson home she shares with her husband and never returns. Last seen wearing a black shirt and pajama pants.
- April 20, 2025 — A friend finds her white Volkswagen at Windy Point Vista on Mount Lemmon. Her phone, purse, and walking stick are locked inside. She is reported missing.
- April 20–26, 2025 — Massive multi-agency search: PCSD, DPS, Tucson PD, U.S. Forest Service, Border Patrol, Southern Arizona Rescue Association. Scent dogs, drones, foot teams. Nothing found.
- April 25, 2025 — PCSD announces it has “exhausted all resources”; case moves to limited continuous mode.
- May 2025 — Friends and professors hold a candlelight vigil at Eller’s McClelland Auditorium. Family launches GoFundMe for a private investigator; offers $5,000 reward.
- 2025–2026 — 857Tucson and Joe Schmoe keep the case public with timeline appeals for footage.
- Today — Still missing.
FAQ
Is Patricia Woo still missing?
Yes. As of October 2026, Hoi Kei “Patricia” Woo has been missing for nearly 18 months. No trace of her has been found.
Was Patricia Woo ever found?
No. Despite an intensive multi-agency search of the Mount Lemmon area in April 2025, nothing belonging to Patricia was ever recovered beyond her car.
What was found in Patricia Woo’s car?
Her white Volkswagen was found April 20, 2025, at Windy Point Vista on Mount Lemmon. Locked inside were her phone, her purse, and her walking stick. Friends said leaving her phone behind was completely out of character.
What is the reward in the Patricia Woo case?
Her family is offering $5,000 for information that helps locate Patricia.
How can I help?
Share this case file. If you were on Mount Lemmon over Easter weekend 2025 (April 18–20) and have dashcam, drone, or video footage, review it and contact the Pima County Sheriff’s Department at (520) 351-4900.
Sources
- Official / law enforcement: Pima County Sheriff’s Department (news release, April 2025; tip line (520) 351-4900).
- News: Tucson Spotlight, “Friends still hopeful in search for missing UA grad” (2025); tucson.com, “Search for missing Tucson woman halted after several days” (April 2025); Eller College of Management student profile (“Hong Kong to Arizona,” 2024).
- Reference: HoiKeiWooMissing (family site, sites.google.com/view/hoikeiwoomissing); GoFundMe, “Help Us Find Patricia Woo.”
- Media: 857Tucson x Joe Schmoe, “PIMA COUNTY MYSTERY: Hoi Kei ‘PATRICIA’ WOO — STILL MISSING.”
Corrections note (fact-verification pass, October 2026): The timeline originally dated PCSD’s “exhausted all resources” announcement to April 27, 2025. The correct date, per the PCSD statement, is April 25, 2025; corrected.
Found an error? Tell us via the About page and we will fix it promptly and note the change here. Last verified October 2026.