Authorities in Florida have arrested a 25-year-old Virginia man, alleging he killed his longtime friend and drove around for a week with the body in his trunk.
In addition, Coltrain is charged with one count of illegal transport of human remains.
The reports, all citing Coltrain's arrest report, indicate that both men were aspiring musicians who had been close friends for more than a decade.
Trotter was reported missing on Oct. 18, according to the Herald. His remains were found a week later on Sunday, in the trunk of Coltrain's crashed silver Acura.
Officers who responded to the scene of the afternoon accident in Miami-Dade had Coltrain's car towed to a nearby mall's parking lot after they allegedly noticed flies buzzing around the trunk and the smell of decomposition.
Police opened Coltrain's trunk and found Trotter's body "wrapped in a piece of fabric and in an advanced stage of decomposition," reports the AP.
Prior to the discovery of Trotter's remains, police said Coltrain asked to remove some of his belongings from the car — including a Glock gun case containing a firearm.
According to police, Trotter, a budding rapper known as Kent Won't Stop, died from multiple gunshot wounds.
Trotter's relatives said they last saw him on Oct. 17, when he was picked up at his home in Triangle, Virginia, by Coltrain.
Victims father said suspect was 'nervous and antsy'
The Miami Herald reports the victim and his alleged killer played sports together and collaborated on music. Trotter's father, also named Brian Trotter, spoke to the paper and said his son had told him the two friends were headed for Washington, D.C., where he assumed they would be taking promotional photos for their music.
"I heard a knock on the door. It was Rob. He was very reluctant to talk to me. I noticed he was acting really strange," the grieving father recalls, of the moment Coltrain arrived to pick up his son. "Usually, Rob comes in the house. This time, he was real distant and nervous and antsy."
Trotter was reported missing the next morning when he did not return home.
Want to keep up with the latest crime coverage? Sign up for PEOPLE's free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.
Trotter's father said that Coltrain stopped answering his phone.
Coltrain allegedly refused to speak to homicide detectives, but police said when Coltrain was allowed his one call, he phoned Trotter's sister — and as detectives listened in, he allegedly apologized and said the death happened in Virginia.
Authorities have not spoken about a motive.
Coltrain has yet to enter pleas to the charges he faces, and remains in custody without bond.
It was unclear Tuesday if he had an attorney who could comment on the allegations for him.