A manhunt is continuing for three inmates who escaped from a jail in California last week by cutting through a grate, climbing through plumbing tunnels and rappelling to the ground from the roof.

Here's a look at the inmates and what happened at the Orange County jail:

WHO ARE THE INMATES?

Bac Duong, 43, Jonathan Tieu, 20, and Hossein Nayeri, 37, were all awaiting trial on separate violent crimes.

Duong is charged with attempted murder in the November shooting of a man in Santa Ana. He has done several stints in federal prison for burglary and drug charges and is the subject of a 1998 deportation order that authorities have not carried out because Vietnam has not provided the required paperwork to take him back.

Tieu is charged with murder, attempted murder and other crimes in a 2011 gang shooting outside a pool hall in Garden Grove. He was 15 at the time of the shooting and was transferred to the men's jail when he turned 18.

Nayeri is charged with kidnapping and torture in a 2012 attack on a marijuana dispensary owner to learn where he might have buried large sums of money.

Nayeri fled to Iran and was arrested by authorities in Prague on his way to visit family.

HOW DID THEY ESCAPE?

Sheriff's authorities say the inmates cut through a quarter-inch-thick grill on a dormitory wall in the Central Men's Jail in Santa Ana and got into plumbing tunnels before sawing through half-inch-thick steel bars.

The men made their way behind walls to an unguarded area of a roof atop the four-story jail building, moved aside razor wire and rappelled to the ground using bed linen, authorities said.

The roof at the jail is commonly used for outdoor recreation. It was involved in prior escapes from the facility, which was built in 1968, said Lt. Jeff Hallock, a sheriff's department spokesman.

DID THEY GET HELP?

Sheriff's officials say there's no indication that anyone inside the jail helped the men, but an investigating was ongoing.

To carry out such an elaborate escape, the men likely were given blueprints or told how the bowels of the jail were laid out, said Kevin Tamez, a managing partner for MPM Group, a firm that consults on prison security, management and infrastructure.

It's unclear how jail officials didn't detect anything inside the dorm where the men were housed with about 60 other inmates. Hallock said the jail's policy is to do walk-throughs every hour, and more involved searches are done at random.

HOW LONG HAVE THEY BEEN GONE?

Authorities said the men were last seen at a 5 a.m. head count on Friday and determined to be missing roughly 16 hours later at an evening head count.

In addition to those two counts, jail personnel check the number of inmates against jail records at three other points during the day, Hallock said. He said investigators have detected some problems with how counts were conducted in this instance.

WHERE MIGHT THEY BE?

Sheriff's authorities said they believe at least two of the men, Tieu and Duong, may be hiding among Orange County's sizable Vietnamese community due to the men's ties to gangs.

Officials have reached out for help from the Vietnamese community, among the nation's largest.

Federal and county officials are offering a combined $200,000 reward for the men's capture.