Officers said they saw Mr. Watson, who was serving a 15-year prison sentence for felony charges of aggravated kidnapping and aggravated child abuse , around 8:30 a.m. on Wednesday at the home of Debra Kaye Johnson, an administrator for the Tennessee Department of Correction. Based on phone records, officials said she was alive and talking on the phone at 8:10 a.m.

Ms. Johnson, who had been with the department for 38 years, lived in a state-owned home on the grounds of the prison, which houses male inmates classified as maximum, medium and minimum security .

Between 9 and 10 a.m., Mr. Watson took a tractor and drove away, according to court records. Prison officials realized he was missing around 11 a.m. and later recovered the tractor a little over two miles away.

When Ms. Johnson, 64, did not report to work, co-workers went to her home and found her body at 11:30 a.m. Investigators discovered ligature marks and a cord wrapped around her neck. The medical examiner’s office determined that she had been strangled and sexually assaulted.

Tony C. Parker, the commissioner of the State Department of Correction, said at a news conference on Thursday that Mr. Watson was qualified to be a prison trusty but declined to discuss it further, saying the policy would be reviewed.