HILO, Hawaii — Authorities are searching for two inmates who escaped from a prison on the slope of Mauna Loa.

The Hawaii Department of Public Safety says Matthew Alani and Lorrin Makapalau were nowhere to be found during a headcount around 8:35 p.m. Friday at Kulani Correctional Facility, which is about 20 miles east of Hilo.

How they were able to escape is still under investigation.

The 25-year-old Alani is described as 5-foot-6, 220 pounds with brown hair and eyes and a large tattoo across his neck. He is serving time for robbery.

The 39-year-old Makapalau is 6-feet, 160 pounds with brown hair and eyes. He is in jail for an escape charge.

Both men have parole hearings next June.

The prison has dorm-style housing for inmates nearing the end of their sentence.