PRYOR-A Mayes County man accused of fatally hitting a man over the head with a baseball bat and then setting him on fire remained in jail Tuesday, held without bail, a prosecutor said Tuesday.

Nicholas Lee Shires, 24, of Pryor, is charged in Mayes County District Court with first-degree murder in connection with the April 28, 2009 death of Michael Cobb.

Wendy Cobb, the victim's then-estranged wife, was in a relationship with Shires at the time of the incident, said Becky Gore, assistant district attorney.

A break in the investigation came earlier this year when authorities received a telephone call from the estranged boyfriend of Shires' mother, according to an arrest affidavit. Through a series of interviews, deputies learned the men were fighting and Shires allegedly beat Cobb with a baseball bat, set the house on fire and stole a motorcycle.

Cobb, an Osage firefighter, was rendered unconscious after being hit over the head, Gore said. The state fire marshal ruled the fire started in the master bedroom, according to the affidavit. Witnesses told authorities they saw an explosion and a ball of fire at Cobb's home. The state medical examiner's report showed a small amount of carbon monoxide was found in Cobb's body, leading investigators to think the firefighter was alive in the fire for a short time.

James Garner, a Pawhuska tattoo artist, told authorities Shires admitted the fatal beating.

He added the slaying had been planned out, including orchestrating the arrival of Cobb at the residence. Shires is scheduled to return to court June 24.

Wendy Cobb has not been charged.