The bodies were discovered in the 2600 block of Riverside Drive. A hazmat team from the Orange County Fire Authority was conducting an investigation.
The identity of the victim or the circumstances behind their deaths was not known. However, investigators said the deaths did not appear to be a result of foul play. They said the man likely had a health issue and died three days ago in the van. The windows were rolled up and the dog may have died of exposure.
Authorities from the Orange County Sheriff's Department and Costa Mesa Police Department were also at the scene and had the street blocked off.