The end of March marked a year since a 29-year-old Ladson man was found strangled in bed at the Cannon Detention Center, reportedly at the hands of his cellmate, Michael Robert Bixby.

Though a State Law Enforcement Division investigation at the time determined Bixby had helped the man, Matthew Lee Glidden, carry out his wish to die, how they came to that conclusion remains largely a mystery. The situation was featured late last year on an episode of MSNBC’s “Lockup Extended Stay: Charleston,” with Glidden briefly chatting days before his death with a film crew about life at the jail.

Bixby, 31, of Indiana, pleaded guilty Monday to the federal child pornography charges for which he had been at the jail awaiting trial at the time of Glidden’s death. The move brought state prosecutors one step closer to resolving an assisted suicide case against the man — a charge deemed questionable by some, considering it appeared on the surface to be based on the word of Glidden’s killer.

Details about what led to Bixby’s child pornography charges are also sparse. A federal complaint and other documents that would further explain the allegations were ordered sealed by a judge in U.S. District Court.

A jury was scheduled to be selected Wednesday to prepare for trial.

Dean Secor, a U.S. attorney who prosecuted the case, confirmed, however, that Bixby ended up pleading guilty to one count of receiving and one count of possessing child pornography.

The receipt charge carries a minimum penalty of 15 years and no more than 40 in federal prison, Secor said. Bixby faces 10 to 20 years on the possession charge. He will be sentenced on a later date.

State prosecutors were awaiting the disposition of Bixby’s federal charges before moving forward with the assisted suicide case they’ve built against him, 9th Circuit Solicitor Scarlett Wilson said.

Wilson declined to comment on the specifics of that case or what evidence they have to support the suicide charge.

“It’s a pending case and the rules of ethics prohibit us from discussing,” she said in an email.

The Charleston County Coroner’s Office last year ruled Glidden’s strangling death a homicide, despite SLED’s findings.

SLED spokesman Thom Berry too declined to offer any insight into the agency’s investigation.

“The Bixby case is awaiting trial. As such, our investigative file is open on this matter. It would be inappropriate for us to discuss specifics of a case that is still open at this time,” he said.

Bixby could face up to 15 years in prison or a $100,000 fine if convicted on the felony assisted suicide charge. An attorney for Bixby did not respond to requests for comment.

Glidden was found dead in his cell about 6:45 a.m. March 24, 2014, while officers prepared the other inmates in his unit for breakfast. He was being held at the jail on charges of criminal sexual conduct with a minor and two counts of lewd act on a child.

Glidden chose to stay in general population at the jail instead of protective custody, despite a code among inmates that could suggested people accused of harming children should be targeted for violence, MSNBC’s “Lockup” reported last year.

Multiple inmates speculated on the show about whether Glidden wanted to die, or if he was the victim of foul play.

Glidden’s mother, Sharon Glidden, told film crews that her son called home the night of his death and described Bixby as an enemy. She said on the show that she didn’t believe her son wanted to die.

“If he had really, really planned this, we thought he would have tried to say goodbye a better way. ... He is dead. I know that and there’s nothing I can do to bring him back. I miss him. I miss him dearly,” Sharon Glidden said. “ I don’t know where I’m going to go from here.”

Reach Christina Elmore at 937-5908 or at Twitter.com/celmorePC.