Air crews search over the Verdugo Mountains in Glendale on Monday, May 14, for Stephen Ivens, 35, a Los Angeles-based FBI agent who was last seen at his Burbank home Thursday night.

Air crews search over the Verdugo Mountains in Glendale on Monday, May 14, for Stephen Ivens, 35, a Los Angeles-based FBI agent who was last seen at his Burbank home Thursday night. (Tim Berger/Staff photographer / May 14, 2012)

An urgent search for an FBI agent who went missing last week stretched into its fourth day on Monday with authorities reporting little progress.

The missing agent, 35-year-old Stephen Ivens, left on foot from his home in the 1700 block of Scott Road in Burbank Friday morning and was reported missing by his family a short time later.

A 40-member search-and-rescue team from the Los Angeles County Sheriff's Department joined about a dozen Burbank police officers and 100 FBI agents in the search for him on Saturday, but despite the massive response and dozens of tips from the public, Ivens remained missing.

For most of Monday, aircrews patrolled the skies above the Verdugo Mountains, where bloodhounds had initially tracked Ivens’ scent.

An avid hiker who is married and the father of a young child, Ivens was believed to be carrying his handgun, although he is not considered to be a threat to anyone but himself, according to authorities.

“There is an “obvious sense of urgency to find him because of the missing weapon and scenarios associated with that that could pose a threat to public safety,” Laura Eimiller of the FBI’s Los Angeles office said.

Authorities have not said why Ivens was despondent, and continued to urge anyone who spots him to call authorities rather than approach him.

Ivens’ scent in the Verdugo Mountains could have been from an earlier hike, Eimiller said, adding that the search was wide open.

“I’m not going to get into the entire investigation, but we don’t want to rule out that he may have gone in another direction,” she said.

[Update: Authorities are relying increasingly on air support because most of the hikable terrain has been covered, Burbank police Capt. Denis Cremins said.

“We looked at trails, and the area adjacent to the trails” in the Verdugo Mountains that people and dogs can access, Cremins said.

Authorities continue to look at cell phone records and credit card accounts and are checking with hospitals on a regular basis, he added.

“The main focus is the Verdugo Mountains but we are not ruling out other areas – we don’t want to get tunnel vision,” Cremins said.]

When asked if Ivens’ had his wallet and cell phone, Eimiller said that only his service weapon appears to be missing.

Ivens is not under any type of disciplinary action by the FBI and by all accounts is a reliable agent, Eimiller said.

Sharon Goewert, a resident who lives a few blocks away from Ivens’ home, said she bumped into him Thursday night.

She had only met the agent once earlier this year during her daily walk through the neighborhood

Goewert said she saw Ivens about 8:10 p.m. Thursday and described him as seeming dazed and stagger on the sidewalk. She said she reported what she saw to the FBI.

Eimiller said she could not comment on specific tips, citing the ongoing investigation. Authorities have received dozens of tips, she added.

Ivens has been with the FBI for more than three years and specializes in national security. He is white, 6 feet tall and weighs 160 pounds, authorities said. He has receding brown hair and wears prescription glasses.

Contact Burbank police at (818) 238-3000 or the FBI at (310) 477-6565.

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