California Highway Patrol started receiving calls about the victim in the road at about 1:40 p.m. CHP responded and reported to the Los Angeles County Sheriff's Department that the man was found lying on the northbound 605 connector to the westbound 60 Freeway.
The man's hands and feet were partially tied, and he had severe burns over his entire body, including his face and head. The sheriff's department said the man appeared to have been assaulted, then lit on fire.
The victim was transported to Kaiser Permanente Medical Center in Baldwin Park, then hospitalized at the burn center at L.A. County USC Medical Center. He was listed in extremely critical condition.
After further investigation, detectives determined that the man had crawled up an embankment to get on the freeway.
"It's a horse trail; there's dirt down there. It's a very tall tunnel, but cars can drive through there," said Detective Mike Digby of the L.A. County Sheriff's Department.
Investigators spent about 14 hours at the crime scene searching for evidence.
A SigAlert was issued for that part of the freeway all afternoon and into Tuesday night.
Anyone with information about this incident is encouraged to contact the Los Angeles County Sheriff's Department's Arson Explosive Detail at (323) 881-7500. If you prefer to provide information anonymously, you may call Crime Stoppers by dialing (800) 222-TIPS (8477), or texting the letters TIPLA plus your tip to CRIMES (274637), or by using the website lacrimestoppers.org.