(CNN) -- A search continued early Monday for a missing FBI agent from Burbank, California, whom authorities have described as suicidal and possibly carrying a handgun.
"There is no evidence of foul play right now, but that is why we still have a robust effort to locate him," Burbank Police Captain Dennis Cremins told CNN affiliate KCAL over the weekend.
Stephen Ivens, 35, was last seen by family Thursday night, a police statement said.
"There is a handgun unaccounted for from inside his residence. There is no indication he is or has been involved in any criminal activity," the statement said. "The police department is concerned for his well-being."
Bloodhounds tracked him in the area of the Verdugo Mountains, police said. "An area that has really rough terrain," according to Capt. Mike Parker.
Ivens, a white male, is 6 feet tall, weighs approximately 160 pounds and wears prescription glasses, police said. He is described as having brown hair with a receding hair line and brown eyes.
Ivens is a Special Agent with the FBI and is assigned to agency's Los Angeles division.
"He worked in national security type cases -- counter terrorism," FBI agent Steven Gomez told KCAL. "That's all I can really say about his casework."