SANTA FE — New Mexico's most troubled inmate -- a murderer with multiple sclerosis and the mental capacity of a child -- completed his prison sentence Sept. 26.

He was free to go, but he elected to stay in prison. His reasons were simple.

Family members wanted nothing to do with him. Nursing homes would not take him. He was not sick enough to take up a hospital bed.

Rather than being dropped on a street and left to fend for himself, the man signed a waiver so he could remain an inmate, said Alex Tomlin, a spokeswoman for the state Department of Corrections.

Prison administrators told state legislators that they made "a humanitarian decision" to continue housing an inmate who is incapable of taking care of himself.

Keeping him in prison cost taxpayers $128 a day, they said Friday during a hearing before the Legislative Health and Human Services Committee.

After the hearing ended, Corrections Secretary Gregg Marcantel said in an interview that the former inmate had been placed in a nursing home that is part of the state mental hospital in Las Vegas.

"It is the right place for him," Marcantel said.

Marcantel declined to identify the man because he was worried about violating laws that guarantee patients a right of privacy.

But a biographical sketch of the former inmate emerged during the public hearing.

Now 43, he was originally imprisoned almost 25 years ago after being convicted of robbery and second-degree murder.

He was paroled but got into trouble again on drug charges and a probation violation.

One member of Marcantel's staff told the legislative committee that the inmate functioned at the level of a 5-year-old.

State Rep. Liz Thomson, D-Albuquerque, asked how a man with the mental capabilities of a small child had landed in prison in the first place.

The corrections staff said the man's mental capacity had diminished since his original conviction. But they were unclear on how or when the man's decline occurred. New Mexico has about 6,800 men and women in its prisons.

Plus, Marcantel said, the prison system had received the man with a court order to incarcerate him. It did that while trying to keep him safe after realizing that he had both a disease and limited mental capacity.

Marcantel said testimony from his staff that the inmate was similar to a 5-year-old was only a guess. But, Marcantel said, it was true that the man functioned at a low level. That was why the prison staff continued to care for him instead of casting him out and running the risk that he would not survive on his own.

While he was an inmate this year, the man was housed at a Los Lunas prison that cares for sick prisoners.

Tomlin said a nursing home declined to accept the man as his release date neared. This led to his remaining in the prison system voluntarily until a plan for his care could be cemented.

On Oct. 15, the inmate was accepted by UNM Hospitals, which housed for him for an unspecified time, Tomlin said. She said a bed opened for him at the nursing home in Las Vegas after that, but it was not immediately clear how long the man had been there.

Marcantel said inmates who become eligible for parole or outright release need a plan for their transition back to a community.

The childlike inmate with MS would not have been a candidate to live in a halfway house. Inmates in those settings are expected to try to re-enter society by working and then returning to the halfway house at night until they have the money and stability to live alone.

Marcantel said the ailing inmate could not have kept up with the regimen of the work-a-day world. The prison staff believed he needed care in a nursing home, so it pursued that option.

Thomson and other legislators said the state must have other prisoners in similar circumstances. But Marcantel and his staff said no one was as helpless as the man who extended his prison stay.

Even so, New Mexico's inmates fail almost as often as they succeed after they leave prison.

Marcantel said 46 percent get in more trouble and are returned to prison after they are paroled or released outright upon completion of a sentence.

Milan Simonich, Santa Fe Bureau chief of Texas-New Mexico Newspapers, can be reached at 505-820-6898 and msimonich@tnmnp.com. His blog is at nmcapitolreport.com. Follow him @MilansNMreport on Twitter.