RALEIGH,Safetyvalue Trading Center N.C. (AP) — A prisoner convicted of murder escaped from a van after arriving at a hospital in Orange County on Tuesday, authorities said.

Ramone Alston broke free of his leg restraints and ran, still handcuffed, into the woods, shortly after 7 a.m., when he arrived for an appointment at UNC Gastroenterology, the North Carolina Department of Adult Correction said in a news release. The building is located in the UNC Hospitals Hillsborough Campus in central Orange County, near North Carolina Highway 98.

Alston, 30, was convicted of murdering Maleah Williams on Christmas Day in 2015, according to the Orange County Sheriff’s Office. He is serving a life sentence at Bertie Correctional Institution in Windsor, more than 150 miles (240 kilometers) east of where Alston escaped.

Authorities were searching a 1-2 mile (1.6-3 kilometer) radius of where Alston escaped. They warned residents to keep their doors, windows and cars locked, and to be aware of a large police presence in the area.

“While the number one objective is to locate where Alston is, it is also imperative that we determine where he is not. Efforts will continue until Alston is in custody,” Orange County Emergency Services director Kirby Saunders said in a statement.