He was being held Tuesday night at Eastern Regional Jail east of Martinsburg.
After the discovery of Mason's body, Martinsburg City Police picked up Catlett on outstanding traffic charges, and he was questioned by West Virginia State Police.
Police were called to Mason's mobile home off Saw Mill Road near Tomahawk after Mason's roommate found his body lying in the trailer, according to state police.
John Ashley, who shared the mobile home with Mason, said he returned home from work Tuesday at about 10 a.m. and found his roommate lying on the kitchen floor.
Ashley said that when he walked to the front of the home, he saw that an outside storm door had been propped open with a picture that had come from inside the trailer.
Ashley said that when he put his key in the inside door to unlock it, he found it was ajar.
Police would not speculate on a possible motive in the death.
Ashley said he did not know of anyone Mason was having problems with and that there had been no previous trouble at their home.
Although there was blood around Mason's body, there was no sign of struggle in the house, Ashley said.
Mason used to live in Virginia Beach, Va., but grew weary of the party scene he had been involved in there and moved to Tomahawk about a year ago to get a fresh start, according to Ashley.
Mason had become active in the youth program at the Hedgesville Assembly of God, helping to lead services and introducing youths to music, he said.
In addition to his church activities, he was a drummer in a Christian music band and had performed at the Alternative Coffee House on West Antietam Street in Hagerstown, said B.J. Gregg, who was a guitarist for the band.
"He had come out of hell and walked into heaven. That's how he felt," said Ashley, who had known Mason for about six years.
Both Ashley and Mason worked at County Market grocery store in Hagerstown, Ashley said. Mason had been experiencing back problems and had not been to work for about a month, Ashley said.
Ashley said the last time he saw Mason was at about 9:15 p.m. Monday when he left for work.
The mobile home is located off American Fruit Growers Road off W.Va. 7.
Michelle Barth, an employee at Tomahawk Valley Store, said Mason frequently came to the store to grocery shop and rent movies. Barth said Mason's death, combined with a missing man near Hedgesville for whom police have been searching the last two days, have made it a frightening time in the area.
"Those two things are enough in one day. It's just scary," said Barth.