Stephen Ivens, 35, has not been seen in days, and now his family and co-workers are concerned about his safety.
Authorities believe Ivens may be suicidal, but they're not saying why. They believe Ivens left his home early Friday morning on foot. His family later reported him missing.
Police believe Ivens took his government-issued handgun, because it was not found in the house.
FBI agents, sheriff's department rescuers and police officers combed the Verdugo Mountains on Saturday after K-9s tracked his scent to the rugged area.
Ivens is known as an avid hiker and runner. However, the FBI agent has been distraught, so his colleagues believe he may have gone to the mountains to harm himself and not to exercise.
"I can't get into the details of why we think he's suicidal, but we have been in discussion with his family and based on just the overall circumstances, we believe there's that potential," said FBI Agent Steven Gomez at a press conference. "He's very well-liked and is a very good person in the community, and that's why we're taking this very seriously and we want to make sure that we are able to find him."
The FBI says foul play is not suspected, and Ivens is not considered a threat to the public - only to himself at this point.
Before becoming an FBI agent three years ago, Ivens was an officer with the Los Angeles Police Department for eight years. He has a wife and a 1-year-old baby.
If you have any information on Ivens' whereabouts, you're urged to contact the Burbank Police Department at (818) 238-3000.