SAN DIEGO — Border Patrol agents found a man dead in the Otay Mountain wilderness Sunday as a heat wave brought scorching temperatures to areas of San Diego County.

A spokesperson for U.S. Border Patrol told FOX 5 that a Border Patrol agent encountered a 55-year-old Mexican man near 13531 Otay Lakes Road around 1 p.m. Sunday.

The man told the agent he was in the U.S. illegally and the person he was traveling with was left behind because he couldn’t continue, the spokesperson said.

Border Patrol Search Trauma and Rescue agents responded to the area where the second person was believed to be.

Cal Fire helped agents find the man, who was dead by the time they reached him, according to officials.

Border Patrol said San Diego Sheriff’s Department was contacted and took over the investigation. The surviving man was taken to a Border Patrol station for processing, agents said.