Rescue crews battle triple-digit heat in search for hiker who went missing 1 week ago in Monrovia

MONROVIA, Calif. (KABC) -- Search and rescue crews battling searing triple digit heat as they comb the San Gabriel mountains for any sign of a hiker who went missing nearly a week ago.

Officials are ramping up the search that is becoming increasingly desperate due to the extreme heat and time-elapsed.

Fifty-three-year-old Collin Walker was last seen getting out of his car trailside at around 6:30 a.m. last Friday at the 900 block of Ridgeside Drive in Monrovia.

Family members, who were out of town when he disappeared, say Walker is an avid hiker who has been doing research for a book on mountains and hiking trails. He normally stays in regular contact with his loved ones, but when he did not check-in on Monday and did not show up for work, he was reported missing.

Detectives found Walker's car still parked near the trailhead, and a search has been underway ever since.

So far, search and rescue crews have found no sign of him.

"The steep terrain, the vegetation and the heat are making progress challenging. However, the search teams are determined to continue all efforts. Ground personnel, air and mounted resources across the state are being utilized to find Collin and bring him home safe as soon as possible," said Chief Brian Solinsky of the South Pasadena Police Department at a press conference Thursday.

Multiple agencies, including police from Monrovia and South Pasadena, as well as a rescue crew from Sierra Madre, are assisting in the search.

Officials are also urging people not to try to find Walker on their own, given the dangers of the extreme heat and terrain.