PLEASANTON, Calif. (KRON) — GPS data from a runner’s smartwatch is giving investigators valuable information for solving the mystery of what happened to Philip Kreycik, an ultramarathon athlete who went missing for nearly a month before he was found dead at Pleasanton Ridge Regional Park.

Kreycik, 37, of Berkeley, was on a trail run when he disappeared July 10, setting off a massive search effort by the Alameda County Sheriff’s Office and hundreds of volunteers.

An autopsy has not been completed yet, but GPS data from his smartwatch is helping investigators piece together what went wrong during Kreycik’s final run.

Philip Kreycik was an ultramarathon runner. (Photo courtesy Facebook/ Find Philip Kreycik)

On the day he died, Kreycik set out on what was supposed to be an 8-mile run along Pleasanton Ridge. The father-of-two parked in Moller Ranch Staging Area and left his phone in the car.

Temperatures soared to 106 degrees that day.

“Those are some of the highest temperatures we’ve had all year out here in Pleasanton,” Sheriff’s Sgt. Ray Kelly told KRON4.

The Pleasanton Ridge Trail is usually a popular place for hikers, mountain bikers, and runners, however, the trail was mostly empty that day because of extreme heat, Kelly said.

Kreycik was a strong ultramarathon runner.

He started his July 10 run at a blistering pace, running 5-minute miles, GPS data from his watch revealed. The watch recorded the runner’s location and pace, but not his heart rate. After 45 minutes of running, his pace slowed down to jogging. Another hour went by and he slowed to walking. He was likely delirious and disoriented when he deviated off the trail and staggered in circles, Kelly said.

“The data shows erratic movement,” Kelly said. “It was likely a heat-related illness, based on everything we know.”

Kreycik’s body was found under a shady tree 24 days later by a search volunteer in Pleasanton Ridge Regional Park.

The Alameda County Sheriff’s Office used drones and scent-tracing dogs during a search effort to find the missing runner. (Photo courtesy ACSO)

Investigators who analyzed the GPS data believe Kreycik died less than five hours after starting his run, which would have been before the search effort began. His wife, Jen Yao, reported him as missing around 2 p.m. July 10 after he failed to return home.

From a preliminary autopsy, the coroner was able to rule out some causes of death.

“We can rule out any foul play, any animal attack, any severe injury,” Kelly said. The coroner may never be able to determine an official cause of death, the Sheriff’s Office said. But investigators are almost certain that the runner suffered from a heat-related medical emergency, such as severe heatstroke.

The runner’s wife had tears streaming down her face as she told a group of reporters, “Life is truly fragile and delicate.”

Kelly said Kreycik was a phenomenal athlete.

“Philip performed at a very high level of running. He absolutely was a gifted runner,” he said. 

Search team combs Pleasanton Ridge. (Alameda County Sheriff’s Office)

Four years ago, he ran a 50-mile race and had the second-fastest time. He finished the Wapack And Back Trail Race in 10 hours, 41 minutes, and 44 seconds. Ultramarathons are races that are longer than 26.2 miles. Some are more than 200 miles.

Ultramarathon runners are known for pushing their bodies hard in challenging conditions, including extreme weather.

Investigators said it appears Kreycik did not have any water with him when he died. The tragedy underscores how important safety precautions are when exercising outdoors, Kelly said. 

Safety precautions include running with a partner, bringing plenty of water, and carrying your phone with you.

Kreycik is survived by his wife, 3-year-old son, and 10-month-old baby.