How did nobody notice? Sheriff releases photographs of the large hole three dangerous inmates cut in the vent screen of their cell before escaping California jail

A frantic manhunt has been launched by Southern California authorities after three inmates charged with violent crimes, including torture and murder, escaped from an Orange County jail by cutting through steel bars and plumbing channels to gain access to the roof.

The dangerous inmates, Jonathan Thieu, Hossein Nayeri and Bac Duong, were last seen at 5am Friday at the Orange County Central Men's Jail in Santa Ana. 

It's been revealed that men cut through half-inch steel bars, made their way through plumbing tunnels and rappelled from the roof using a makeshift rope at the jail, which is about 40 miles southeast of Los Angeles. 

They could have escaped anytime between then and late Friday night, Lt. Jeff Hallock, a spokesman with the Orange County Sheriff's Department, said Saturday.

'This was clearly a well thought out and planned escape' that may have been in the works for weeks or months, the lieutenant told reporters Saturday afternoon, reported KTLA.

Scroll down for video 

Wanted: Southern California authorities launched a frantic manhunt Saturday after inmates (left to right) Jonathan Thieu, Hossein Nayeri and Bac Duong escaped from jail 

Above is pictured the jail cell and vent screen that had been cut, near the floor at center rear, inside of the Central Men's Jail in Santa Ana, California by the three inmates

The vent screen (above) had been cut and removed from the inside of the jail cell where the three men escaped from sometime on Friday, January 22

A cord made of an undetermined fabric that facilitated the escape of three inmates is pictured above inside the Central men's Jail in California

Officials said the inmates cut through half-inch steel bars and plumbing tunnels to gain access to an unsecured roof. Photographs released by authorities on Sunday show the hole cut and rope used in the escape.

All three men then used cord made of an undetermined fabric to rappel down four stories to the ground and fled on foot in their orange jumpsuits.

According to The Los Angeles Times, there was a fight inside the jail around 8pm that might have been part of their escape plane. 

The fight delayed the headcount, which normally takes place at that hour. 

The three escapees were able to get past security check points in at least three areas, the Times reported. 

The exterior of the jail showing where razor wire was removed from a parapet, center rear, and a rope-like line, seen at right, is pictured above. Authorities believe the three inmates used the rope-like line to repel to the ground during their escape

Investigators are pursuing several leads in their search, and in the meantime a separate probe was launched into how the inmates managed to obtain the tools to cut through the steel bars and plumbing tunnels to make it to the roof of the facility (above)

Lt. Jeff Hallock said the Orange County Sheriff's Department is doing everything it can to find the men

It's unclear how they acquired the tools and how they went undetected.  

Hallock said it's the first escape from the facility in at least the past 20 years and could be the first-ever breakout from the jail.

The inmates include Tieu, 20, who had been held on a $1million bond since October 2013 on charges of murder, attempted murder and shooting at an inhabited dwelling. His case is believed to be gang-related.

Nayeri, 37, had been held without bond since September 2014 on charges of kidnapping, torture, aggravated mayhem and burglary.

'The three escapees ... are dangerous criminals,' Orange County Sheriff Sandra Hutchens warned in a statement.

Orange County sheriff's deputies and a search dog investigate early Saturday morning after the inmates' escaped

'My investigations team is working around the clock with the Orange County District Attorney's Office, the Orange County Probation Office, the US Marshals and the FBI.

'I am confident that this collaborative effort will result in returning these inmates to where they belong -- behind bars.' 

Nayeri and three other men are accused of kidnapping a California 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, Duong, 43, 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.

Lt. Jeff Hallock said at a news conference 'We're exhausting all investigative resources and measures to bring these three inmates back into custody'

Hallock said the sheriff's department is doing everything it can to find the men.

'Obviously the safety of the community is No. 1,' Hallock said at a news conference. 

'We're exhausting all investigative resources and measures to bring these three inmates back into custody.'

A $20,000 reward is being offered by the FBI for information leading to the arrest of any and all escapees. 

They could have escaped anytime between Friday morning and late Friday night, Lt. Jeff Hallock said

Have you seen these men? The Orange County Sheriff's Department has released this bulletin asking the public for help in locating the escaped inmates