Acting on a tip, investigators found Smith's black 2000 Mercedes-Benz 420E in a Simi Valley storage locker Feb. 21.
"I can't say anything about what we found in the car," said Los Angeles County Sheriff's Department Lt. Dave Dolson. "I'm not going to talk about the exact evidence, but we'll just say that the condition of the vehicle leads us to the conclusion, in conjunction with some witness statements, that Gavin was most likely murdered."
The storage locker was rented by someone very close to a man named John Creech, who is currently in custody at Men's Central Jail on an unrelated narcotics conviction. Investigators say Smith had some kind of relationship with Creech's wife.
"We don't want to get into his personal life, but there was a relationship with his wife, they met in rehab," said Dolson.
Smith was last seen at a friend's residence in Ventura County's Oak Park area on May 1, 2012. He was driving his Mercedes. Since then, search for Smith has been a rigorous one. In January, deputies impounded and searched Creech's Hummer. Last June, they also searched Creech's Canoga Park home. Smith's family members went on their own search following his disappearance.
Smith's wife said in a statement Thursday, "The family of Gavin Smith is grateful to the Los Angeles County Sheriff's Department for its unending work on his disappearance. We are both saddened and heartened by the discovery of this crucial evidence, and know that the sheriff's department will help us acquire a measure of justice."
Smith's body has not been found. At this point, Creech is a person of interest and not a suspect.
"We have found evidence at numerous locations," said Dolson. "We have a lot of evidence, and a lot of evidence that still needs to be analyzed."
Detectives are trying to find out who moved the Mercedes Benz from the Porter Ranch area to the storage facility on or about May 8 or 9. They say they do believe the killer had some kind of help in the crime.
"We believe that there are other people involved in the aftermath, the moving of the car and movement of the body," Dolson said.
Anyone with information is urged to call the Los Angeles County Sheriff's Department Homicide Bureau at (323) 890-5500.