SAN DIEGO -- A man described as a designated driver was in custody Monday, booked for alleged DUI and vehicular manslaughter, following a fiery crash that killed a man in Torrey Pines, police said.

Michael Patrick Landri was driving an Infiniti G35 that rear-ended a Volkswagen Passat at Genesee Avenue and Torrey Pines Road around 10 p.m. Sunday, causing both vehicles to burst into flames, according to the San Diego Police Department.

A bystander pulled Landri and a "very drunk" male passenger from the burning Infiniti but was unable to rescue the driver of the Passat, police said. The men in the Infiniti were on their way home from an employee Christmas party, according to police.

The driver of the Passat has been identified as Jared Franklin Purton, 33, of Pacific Beach, according to the San Diego County Medical Examiner's Office.

Landri was arrested on suspicion of gross vehicular manslaughter and drunken driving counts and booked into San Diego Central Jail, according to jail records.

Police said Landri was supposed to be a designated driver -- a person who refrains from consuming alcohol in order to safely drive home passengers who have imbibed.