The probable mastermind in the brazen escape of three inmates from a California jail had help from a woman whose English classes he was taking while locked up, authorities allege.

Escapee Hussein Nayeri, 37, came to know Nooshafarin Ravaghi, 44, during an English as a second language course inside the Orange County jail.

Investigators believe a close relationship developed between the two, who had exchanged handwritten letters of a "personal nature," sheriff's spokesman Lt. Jeff Hallock said.

"It wasn't the relationship that you would expect between a teacher and an inmate in a custody setting," he said, noting that jail employees go through training about rules and the risk of being manipulated by inmates.

The escapees remained at large Friday, and Hallock said investigators believed they were still in the region.

Nayeri's past and sophistication among other factors led Sheriff Sandra Hutchens to tag him as the likely mastermind of the Jan. 22 elaborate escape. The prosecutor in the kidnapping and torture case against him was so alarmed by his escape she described him in an interview with a reporter as a Hannibal Lecter, the sadistic killer in "The Silence of the Lambs."

Nayeri and two other inmates, 43-year-old Bac Duong and 20-year-old Jonathan Tieu, sawed through a metal grate over a plumbing tunnel and sliced through more metal and rebar to reach an unguarded section of roof, where they rappelled down with bed linens, authorities said.

Their need for strong tools to cut their way out had led to investigators believing they must have had help, the sheriff said. Ravaghi, the teacher, denied providing the men those tools, but officials say her assistance included providing them with Google Earth printouts of the entire jail complex.

She was booked for investigation of being an accessory to a felony and faces arraignment Monday.

Duong stole a van the day after the escape after taking it for a test drive in the only reported sighting of the men since the breakout. Investigators believe the three men may be traveling while living out of the back of the white GMC Savana, Hallock said.

Nayeri's attorney, Salvatore Ciulla, did not return a request for comment, and authorities did not know Thursday whether Ravaghi has yet obtained an attorney.

Nayeri moved to the U.S. with his family as a child. He attended high school in Fresno and then joined the Marines.

He had no felony record in 2005 when he was charged in a drunken-driving accident that killed his high school friend, Ehsan Tousi, and left Nayeri hospitalized with burns and struggling with depression, according to friends and family.

While free on bail, Nayeri fled but eventually was arrested in Washington and extradited to California in 2009. At his sentencing, friends and family wrote letters to the judge on his behalf, saying the accident had turned him into a shell of his former self.

He hung a photo of Tousi on the wall of his hospital room and cried daily, one friend wrote. A sibling wrote that he stopped calling and spent hours at his friend's gravesite.

"It was a horrible feeling to watch my little brother drift away, but there was nothing I could do," Sheri Nayeri wrote the judge.

Nayeri told the judge he remembered the smell of burning flesh and was screaming his friend's name before he blacked out.

He was sentenced to less than a year in county jail and four years of probation, in part because of his lack of felony history.

His criminal record subsequently grew, and he was on probation in 2012 when, prosecutors say, he fled during a traffic stop in Orange County and led police on a high-speed chase before getting away.

About a week later, prosecutors say, Nayeri and three others kidnapped a medical marijuana distributor, bound him with zip ties and drove him to desert where they believed he had buried a large sum of cash.

There, the man was tortured with a blow torch, according to court files.

As authorities closed in on Nayeri, he fled to Iran. He was arrested in 2013 in Prague as he tried to travel to Spain to meet his family.

He was to go on trial Feb. 23 on charges that include kidnapping, torture and burglary.