Wesley Spratt's house of worship is a cramped, windowless chapel at a maximum-security prison. A cross adorns a cinderblock wall and eight wooden benches seat the inmate congregation.

Spratt, a convicted killer with a life sentence and a professed calling from God, prays inside this sanctuary every Friday evening. He preaches here, too, lecturing on sin and salvation and reciting favorite Bible passages.

When a warden made him stop, Spratt sued. This summer he won his case and the right to resume spreading the Gospel, which he does. He preaches to anyone and everyone willing to listen.

"I've prayed with everybody," Spratt, imprisoned for the 1995 murder of a parking lot attendant, said in a prison interview. "I don't care who you are — child molester, bank robber, stick-up kid."

The legal challenge, ultimately decided by a federal appeals court, pitted Spratt against the state in a fight over religious expression.

Clergymen who know him vouch for his evangelical fervor, while the family of the victim, Christopher Naylor, regard Spratt as an unrepentant phony. Spratt maintains his innocence, even though the state's highest court has upheld his conviction.

"Everyone finds God in prison," said Naylor's brother, Michael Naylor, a former prison guard and police detective. "They seem to lose it as soon as they walk out the door."

Spratt, 47, is a former pimp who says he had all the clothing, jewelry and women a man could want.

"Before he was there, he was in the streets and wild and did everything wrong," said the Rev. James Turnipseed, who leads the services where Spratt preaches. "So he can relate to the guys."

Spratt, who was raised Protestant, says he always had a relationship with God, but it wasn't until he arrived in prison more than a decade ago that he fully immersed himself in Christianity. He devoured the teachings of the Bible, filling copies with notes and participating in study sessions.

His faith was solidified by what he describes as an out-of-body experience: the Holy Spirit descended upon him, he said, soon after he was put behind bars, as he was awaiting trial.

"My body was quivering, my face was all numb and the spirit of God pulled me out of my body," he recalled.

When he recites Scripture, he does so in a breathless cadence, his eyes widening and his forearm moving in emphasis as he quotes Romans, Ephesians and Revelation.

He tells fellow prisoners that salvation comes not through good deeds but through faith.

Turnipseed calls Spratt the most zealous inmate he has ever met.

"Wherever he is, he is talking about his commitment to Christ," he said. "If he's in the yard, when the other guys are playing ball or something, he's talking about Christ."

Spratt preached weekly for about seven years, in the prison chapel and cafeteria.

"I've witnessed many men packing the chapel to hear him preach and at least half because they knew him from the street and were impressed," prisoner Ronald Fortune wrote in a letter to The Associated Press.

In 2003, a new warden, James Weeden, banned prisoners from preaching, saying it posed a security risk to place inmates in positions of authority.

"People behind a pulpit are in a position of power," Weeden said. "And people behind a pulpit, of all faiths, have abused that power."

Spratt said he challenged the ban because it interfered with his calling.

"It's like having a basketball player who knows how to play good — he's Michael Jordan, he's whatever — and you bring him to the basketball game and you sit him on the bench the whole game when he's not injured and there's nothing wrong with him," he said.

Acting as his own attorney, Spratt sued in federal court in 2004. The lawsuit caught the attention of the state chapter of the American Civil Liberties Union, which pursued the case, saying the ban violated inmates' rights to exercise their religion.

The 1st U.S. Circuit Court of Appeals in Boston ruled against the ban, calling Spratt's preaching "apparently unblemished by any hint of unsavory activity" and remanding the case to a lower court. Both sides settled in July, agreeing that Spratt and other inmates could preach under certain restrictions, including having supervision.

Spratt immediately resumed preaching.

He maintains that he was maliciously prosecuted and wrongly identified at trial as Naylor's shooter. The state Supreme Court rejected his appeal, and the attorney general's office says there's no doubt of his guilt.

"I wish that he would just serve his time and do good things," said Naylor's widow, Linda Murgo. "I don't believe that his preaching is a good thing because I don't believe he is sincere."

Spratt is eligible for parole in 2019. He says he won't be in prison a second longer than God wants him to be.