Bloodhounds had initially tracked Ivens' scent to the Verdugo Mountains, but later determined it could have been from an earlier hike.
In the days after he was first reported missing, 100 FBI agents joined local police and L.A. County sheriff's deputies for what officials said was the largest manhunt of its kind in Burbank.
Ivens, who has been with the FBI for more than three years and specializes in national security, was only believed to be threat to himself, although authorities declined to elaborate why.
In a public letter appealing for his safe return earlier this week, his wife, Thea Ivens, said her husband "would never hurt or be a risk to anyone."
“He is a father, a husband, a son, a brother, a nephew, a friend and a colleague in this community," she wrote.
Burbank police on Friday again appealed for the public's help in tracking Stephen Ivens down. Those with information may call police at (818) 238-3000, or the FBI at (310) 477-6565.
Stephen Ivens is white, 6 feet tall and 160 pounds, authorities said. He has receding brown hair and wears prescription glasses.
Authorities have urged the public to not approach the agent, but to instead notify police.
-- Jason Wells, Times Community News