MONTGOMERY, Ala. — An inmate serving a life sentence for human trafficking escaped from an Alabama prison by hiding inside a trailer used to haul furniture, state officials said Friday.

Law enforcement authorities are continuing to search for 30-year-old Corey Aris Davis, who escaped from the St. Clair Correctional Facility in Springville on Wednesday.

The Alabama Department of Corrections issued more details about the escape and said they are also investigating why the inmate was not reporting missing for nearly eight hours.

Investigators determined Davis hid inside the trailer while he was working in the prison furniture plant and used a piece of furniture to conceal himself, Alabama Department of Corrections spokesman Bob Horton wrote in a statement. He said the trailer left around 12:30 p.m. Wednesday for another prison industries facility in Montgomery.

Investigators believe Davis has left the Montgomery area. Authorities were searching for Davis in north Alabama on Thursday following a possible sighting.

Prison officials believe three other inmates helped Davis escape. Investigators are trying to determine how Davis got into the trailer unseen and why he was not reported missing until a security check at 8 p.m. Wednesday night.

The Alabama prison has been placed on lockdown during the investigation.

Davis was sentenced to life in prison in 2017 for two charges of human trafficking in Lauderdale County, records show.

Court document shows Davis had faced charges of sexual torture, rape, sodomy, kidnapping and burglary, but he agreed to plead guilty to human trafficking.