Authorities are seeking the public’s help in locating a 61-year-old San Diego County man who sheriff’s officials say went missing under suspicious circumstances.

Investigators began their search around 7 a.m. Wednesday for Frank Torres, a resident of Pauma Valley in rural North County, after family members reported him missing Tuesday, according to the Riverside County Sheriff’s Office, which is investigating the case.

During the investigation, Torres’ vehicle was found abandoned near a park in Temecula, officials said.

Homicide investigators identified Derek Arnett, 66, as a person who was wanted for questioning in Torres’ disappearance. He was located driving in Temecula near Wolf Valley Road and Wolf Valley Creek Drive on Wednesday. The vehicle eventually stopped in a parking lot off Pechanga Parkway, the agency reported.

Believing Arnett was armed with a gun, deputies called in the sheriff’s Emergency Services Team for assistance. When deputies approached the vehicle, they found him with injuries consistent with an apparent self-inflicted gunshot wound, officials said. Arnett died at the scene.

No details on Arnett’s relationship, if any, to Torres have been released.

As of Friday, Torres remains missing, and officials have not disclosed further information about what makes his disappearance suspicious.

Authorities urged anyone with information regarding Torres’ whereabouts to contact homicide Investigator Hernandez at 951-955-2777 or Southwest Station Investigator Mills at 951-696-3000.