HUNTSVILLE, Texas — Two inmates working in a prison field overpowered a female guard today and killed her when they ran her over in a stolen pickup truck as they fled, prison officials said.

One of the prisoners, John Ray Falk, was recaptured within the hour. The second, Jerry Martin, was found several hours later hiding in a tree after a manhunt that included a police helicopter, Stetson-hatted lawmen on horseback and bloodhounds.

Martin and Falk were working outside the Wynne Unit of the Texas Department of Criminal Justice just north of Huntsville when they overpowered the officer about 10:30 a.m. along Interstate 45, took her weapons and stole a Huntsville city truck that was nearby, a corrections department spokesman, Jason Clark, said.

“They ran over the officer,” Mr. Clark said. “We can confirm she did die.”

The guard, Susan Canfield, 59, had been a corrections officer for seven years, a Texas Department of Criminal Justice spokeswoman, Michelle Lyons, said.

After the inmates took the truck, they at some point stole another vehicle and ditched it, too, Ms. Lyons said.

Mr. Martin, 37, had been imprisoned since 1997 and was serving a 50-year sentence for attempted murder. Mr. Falk, 40, had been serving a life sentence since 1986 for murder.

Based on his good disciplinary record in prison, Mr. Martin was classified as a minimum security inmate and assigned to do field work outside the prison under supervision.

“In this case, obviously, something went wrong,” Ms. Lyons said. She said Mr. Martin did not appear to be hurt, and would face felony escape charges “at the very least.”

The Wynne Unit, established in 1883, is one of the oldest in the Texas prison system. It holds about 2,600 inmates of various custody levels. The unit is about 80 miles north of Houston and shares about 1,500 acres with two other prisons that straddle the main freeway between Houston and Dallas.

Authorities in Utah were also searching for a pair of fugitives today after two convicted killers escaped from a county jail near the Utah-Wyoming border.

Danny Martin Gallegos, 49, and Juan Carlos Diaz-Arevelo, 27, escaped yesterday after jumping the fence at the Daggett County jail, about 120 miles east of Salt Lake City, a spokesman for the Utah Department of Corrections, Jack Ford, said. He said the men were discovered missing during an inmate count at 8 p.m. — six hours after they were last seen at the jail.

“Both men are considered dangerous. Do not approach,” the sheriff’s office said in a statement.

Gallegos was convicted of aggravated murder in 1991. Diaz-Arevelo was convicted of murder and child abuse in 2006. Because of overcrowding, the two men had been transferred to the jail from the state prison, Mr. Ford said.

In north Georgia, a search ended for three inmates who escaped last night from Fannin County Jail in Blue Ridge, authorities said. They were all in custody by this afternoon, Trooper Larry Schnall said.