DALLAS - Authorities are trying to piece together just how a capital murder suspect was able to take a deputy's gun and escape from a Dallas hospital before he was cornered a mile away and surrendered.

Franklin B. Davis, 30, of Carrollton, stole the deputy's service revolver and fled Parkland Memorial Hospital about 8:30 p.m. Tuesday, beginning a manhunt that ended with a standoff as he hid in a barbecue delivery van about a mile south of the hospital. Davis took refuge in the van about 9 p.m. and kept police at bay with the stolen weapon for about two hours before negotiators talked him into a peaceful surrender, Dallas County sheriff's spokeswoman Carmen Castro said.

No new charges were filed against Davis as police and deputies investigated the episode, Castro said.

Davis surrendered shortly before 11 p.m. Tuesday and was returned to the same hospital from which he had escaped while receiving treatment, Castro said. She did not know what kind of treatment Davis was receiving, she said.

The deputy was not injured in the incident at the hospital, she said.

Davis is awaiting trial in the death of Shania Gray, a 16-year-old sophomore at Hebron High School in Carrollton. Her body was found Sept. 8 along a fork of the Trinity River. She had been shot and strangled.

Davis already had been charged with four counts of sexually assaulting Gray when he allegedly took Gray from her school. Police have said Davis confessed to killing the girl. Police say he did so to prevent Gray from testifying against him in a sexual assault case.

Family and friends had said that when she was killed Gray's family was in the process of moving from one Dallas suburb to another so her father could be closer to work. Neighbors in Mesquite, the eastern suburb where the family lived for years, described Gray as friendly and caring.

According to relatives and an affidavit released by Carrollton police, Davis posed as a teenage boy on Facebook and bought a new cellphone to contact Gray and get information about the sexual assault case.

The two exchanged text messages, though Carrollton police spokesman Jon Stovall said he didn't know how many.

Davis told Carrollton police Gray was surprised to see him when he pulled up to her outside her school but got into his car because he wanted to discuss the case. He told police and several television stations that he drove her to an area near the Trinity River and shot her twice. He then stepped on her neck until she stopped breathing, the affidavit said. Her body was found two days later.