D.C. police are looking for a prisoner who allegedly ran off after arriving at a Southeast hospital just after midnight Sunday.

Police said 27-year-old Derrick Ross-Simms was last seen outside United Medical Center, which is located in the 1300 block of Southern Avenue, Southeast.

Ross-Simms arrived at the hospital for treatment at around 12:31 a.m. on Sunday. In a news release, police said he escaped from officers and ran away.

Police put out photos of Ross-Simms, and asked anyone with information to call the department at (202) 727-9099 or text a tip to 50411.

Police didn’t specify what treatment Ross-Simms went to the hospital for.

Ross-Simms was previously arrested and charged with carrying a pistol without a license and possession of a control substance, police said.

Police have issued an arrest warrant related to the alleged escape.