PLEASANTON, Calif. (KRON) — A 37-year-old runner has been missing since Saturday – the search continues for him Monday in the Pleasanton Hills Regional Park area.

Philip Kreycik came to the Moller Ranch Trail on Saturday around 11 a.m. for a 6-8 mile run which should have only taken about 45 minutes to an hour.

But authorities say he never returned home that day.

Kreycik lives in Berkeley and drove out to Pleasanton for the run. His wife called the police when he never returned. The MIT grad had been running in Pleasanton before, officials said.

They are considering an assumption that he could have been hurt somehow while running during the heatwave. It was about 100 degrees in Pleasanton on Saturday.

Police found his car in the parking lot of the trailhead with his phone inside where they discovered an app showing his running route.

An extensive search began along that route and in the surrounding area.

Pleasanton Police Department, the Alameda County Sheriff’s Office, CHP and volunteers have been using a ton of resources to try and find him.

After two long days of searching, police are not losing hope.

The search area is a steep, rugged and canyon-type terrain with a lot of trails going left and right.

On Monday morning, the search and rescue command center was moved to Foothill High School so crews can enter the hills in Pleasanton from a better vantage point.

Police say right now they do not suspect any foul play and do not believe Kreycik wanted to disappear. He was a tech worker and a member of a local runners club.