Local and federal investigators throughout Southern California are searching for three “dangerous criminals” — including a suspected killer — who pulled off a brazen escape from a maximum-security jail that required the trio to cut through steel bars, navigate plumbing tunnels and rappel off a roof about five stories high.

“Obviously, the concern is that they are desperate,” Lt. Jeff Hallock, of the Orange County Sheriff’s Department, told reporters at a news conference Monday. “They’re facing some very serious charges. Again, that’s why we’re pleading for the public’s help because we know someone out there knows something.”

“We’re receiving tips, but not of the quality that we’d like,” he added, noting that investigators have had no sightings of the men so far.

Hallock said investigators suspect Jonathan Tieu, 20, Hossein Nayeri, 37, and Bac Tien Duong, 43 — who escaped from the Orange County men’s jail before dawn Friday — may have fled back into the Los Angeles metropolitan area, where all three have close ties to local gang members.

There is no credible information indicating that the men have tried to cross the Mexican border, Hallock said, but authorities are leaving open the possibility that the escapees might try to do so. He said investigators think the men are likely armed and may be receiving assistance through their criminal ties.

“We sincerely need input from the community to help us put these three dangerous individuals back into custody,” said Orange County Sheriff’s Lt. Dave Sawyer, who is leading the probe into the escape.

“We feel that they may be embedded somewhere in the community and that’s why we’re reaching out to the community and letting them know. We understand that you’re in danger, we understand that you’re fearful. We understand that you may be fearful about coming forward with information about where these individuals are located.”

He added: “We can keep you anonymous if you want to remain anonymous, but we need the information to help us go forward to find these people.”

The men were dressed in orange jumpsuits when they fled the jail Friday morning, according to the Orange County Sheriff’s Department. They were last seen before daybreak and were discovered missing from the jail, about 32 miles southeast of downtown Los Angeles, during a Friday-night head count, the sheriff said.

“We will not stop until these individuals are back in our custody,” Orange County Sheriff Sandra Hutchens told reporters. She added that the escape was “a very sophisticated-looking operation,” according to Fox News.

Hutchens has called the three escapees “dangerous criminals” and said sheriff’s investigators are working “around the clock” with county prosecutors and probation officers, the U.S. Marshals Service and the FBI.

“I am confident that this collaborative effort will result in returning these inmates to where they belong — behind bars,” Hutchens said.

Tieu is charged with murder, Duong with attempted murder and Nayeri with kidnapping and torture, according to the Los Angeles Times.

Nayeri is accused of kidnapping a California marijuana-dispensary owner in 2012, according to Fox. The victim was taken to a remote desert location to retrieve money before Nayeri and two other men cut off his penis, authorities told Fox.

Authorities said a $50,000 reward is available for information leading to the men’s capture.

As the manhunt intensified, Tieu’s sister, Tiffany, begged for her brother to surrender.

“Please just turn yourself in,” she pleaded in an interview with KABC. “Don’t let this drag on.”

Tiffany Tieu told KABC that she doubted the escape was her brother’s idea.

“I for sure, I know he wasn’t the one that orchestrated this, so I feel like he was manipulated or tricked into doing this,” she told the station.

Hallock said it was the first escape from the 900-inmate facility in at least two decades.

“I think the public should expect the worst if they’re encountering them and call 911 and allow the professionals to respond,” Hallock said, according to Fox News.

The Times described the jail — which was built in 1968 — in the following way:

The Men’s Central Jail is a hulking concrete compound in Santa Ana’s civic center, its sheer concrete walls rising several stories. The roof is lined with loops of barbed wire.
The jail sits in a busy district of the city’s downtown, home to government offices, courthouses and a soccer stadium.

Authorities said they’re in the process of reviewing security footage to better understand how the escape unfolded. Investigators said it may have taken months to prepare.

The escape, the Times reported, may have begun with an altercation involving a deputy before the evening head count.

Hutchens said the inmates managed to move through three security points, giving them access to the building’s plumbing system. They used bedsheets to rappel from the jail roof and tools to slice through metal bars, but authorities have yet to determine how they came to possess the tools.

“I’ve been in law enforcement for 37 years, always working for sheriff’s departments that manage jails. And escapes do occur from time to time,” Hutchens said. “We try and limit that. We learn from the mistakes.”

She added, “People in jail have a lot of time to sit around and think about ways to defeat our systems.”

This post has been updated.