"We will not stop until these individuals are in custody," Sheriff Sandra Hutchens said Sunday morning at a news conference. "I want to tell the public: Presume that they are armed and do not approach them."
The inmates - one of whom is an alleged killer - were last seen at 5 a.m. Friday at the Orange County Central Men's Jail. Lt. Jeff Hallock said at a later press conference investigators believe the men escaped shortly after the last count.
Hallock said the inmates cut through plumbing tunnels and finally made it to an unguarded area of the roof where they were able to rappel to the ground using some kind of makeshift rope.
Surveillance footage of escaped inmates accessing unsecured area of CMJ's roof
Their escape was "well thought out" and the result of weeks or even months of planning, Hallock said. It's unclear whether they had any help from the outside or if other inmates were involved in the escape.
"People in jail have a lot of time to sit around and think about ways to defeat our system," Hutchens said.
The inmates include 20-year-old Jonathan Tieu, who had been held on a $1 million bond since October 2013 on charges of murder, attempted murder and shooting at an inhabited dwelling. His case is believed to be gang-related.
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Hossein Nayeri, 37, had been held without bond since September 2014 on charges of kidnapping, torture, aggravated mayhem and burglary. Nayeri and three other men are accused of kidnapping a marijuana dispensary owner in 2012. They drove the dispensary owner to a desert spot where they believed he had hidden money and then cut off his penis, authorities said.
After the crime, Nayeri fled the U.S. to his native Iran, where he remained for several months. He was arrested in Prague in November 2014 while changing flights from Iran to Spain to visit family.
The third escaped inmate, 43-year-old Bac Duong, was being held without bond since last month on charges of attempted murder, assault with a deadly weapon, shooting at an inhabited dwelling, being an ex-felon in possession of a firearm and other charges.
Hossein's last known address was in Newport Beach, Tieu's was in Fountain Valley and Bac's was in Santa Ana.
"Each of the three should be viewed as very dangerous. We don't have any specific information that they are armed, but I think the public should expect the worst if they're encountering them," Hallock said.
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Hutchens says investigators have gotten a number of "very good tips" but have had no concrete sightings of the men.
There have been two prior escapes from the 900-inmate facility but both took place over 20 years ago.
Hutchens says there's no indication any of them have left the country. Local and federal authorities in several counties are searching for the men.
Anyone with information on their whereabouts was urged to call the Orange County Sheriff's Department hotline at (714)628-7085. Those wishing to remain anonymous may call Crime Stoppers at (855) 847-6227.
City News Service and The Associated Press contributed to this report.