Authorities searched rolling ranchland Tuesday for two convicted murderers and two people awaiting trial on capital murder charges who escaped from a jail by overpowering two female guards with a homemade knife.

Two of the fugitives were serving life sentences for the 1996 murder of a 16-year-old Oklahoma cheerleader. The other two — a man and a woman — were arrested in November and charged with killing an elderly Montague County couple on whose land they had been living.

"These are some of the most dangerous individuals that exist in our society," District Attorney Tim Cole said.

"There's no question in my mind they'll arm themselves at the first opportunity," Cole said of the escaped inmates. "The two men with life sentences just have absolutely nothing to lose."

Members of the public "need to be very careful," Cole said.

Roadblocks were set up and the FBI joined the search near the Red River along the Texas-Oklahoma line for the fugitives, who broke out of Montague County Jail late Monday.

Cole said the escapees were believed to be headed to Oklahoma and possibly other states, including Missouri and Oregon. It was not known if they had stayed together or split up.

"We have just about everybody out just in case they slip through," said Dee Hazle, a dispatcher with the Jefferson County sheriff's office in Waurika, 45 miles northwest of Montague.

Cole said they used a homemade knife to overpower two female guards, then walked out a back door and drove off in one of the guards' sport utility vehicle. The guards were not hurt.

He said the jail houses about 50 inmates and was full at the time of the breakout. "There's a real overcrowding problem here, but that's no excuse for lousy security," Cole said.

The fugitives were identified as Curtis Gambill of Terral, Okla.; Joshua Bagwell of Waurika, Okla.; and Chrystal Gale Soto, 22, and Charles Jordan, 30, of Bowie, Texas.

Tuesday morning, at least one discarded black-and-white-striped jail uniform was found under a tree near the jail, said an employee at a nearby bail bond agency.

"I thought, 'Oh my God, those are their clothes.' I was surprised nobody had seen them," Tara Vicari said.

Gambill and Bagwell were convicted in the Oct. 2, 1996, murder of Heather Rose Rich, 16, of Waurika, Okla.

Soto and Jordan were arrested on Nov. 28, in Mason County, Wash., two days after the bodies of James Christmas, 76, and his wife, Ullain, 79, were found in a shallow grave on land they owned near Bowie, 11 miles southeast of Montague.

On Jan. 16, Gambill received a second life prison term after a judge found him guilty of conspiracy to commit murder in the cheerleader killing. Gambill waived his right to a jury trial last summer.

Gambill's first life sentence was handed down in 1997 after he pleaded guilty to killing the cheerleader. Two years after Gambill pleaded guilty to murder, Cole refiled the conspiracy charges, saying Gambill reneged on the plea deal by testifying at Bagwell's trial that another man was the killer.

Bagwell was in the jail as a possible witness against Gambill, but was never called. Bagwell and Gambill were awaiting transfer back to the state prison system, officials said.