DETROIT (Reuters) - A Michigan murder trial over the killing of a man who was castrated has revealed an apparent torture chamber in the basement of a suburban Detroit house where men were castrated for sexual purposes.

Robert Martin Nowak, 51, is charged with murder and criminal sexual conduct in the killing of 26-year-old Troy Moross, whose body was found near a machine shop where Nowak was working and living part-time in 2001, the Oakland County prosecutors office spokesman said.

He had been castrated.

Nowak's attorney Larry Kaluzny said he will present evidence at the trial on Monday that federal authorities were investigating a group of men involved in a castration cult operating out of a house in Rochester Hills.

He will try to prove that the ring of men, whom investigators say also operated a torture chamber in the basement of the Rochester Hills house, may have been involved in Moross' killing, and not his client.

Kaluzny said he cannot deny that physical evidence shows that Nowak had sex with Moross, but he will try to convince the jury that someone else, perhaps one of the men in the house in Rochester Hills, could have killed him.

DNA found under Moross' fingernails, Kaluzny said, indicate he struggled for his life and scratched his attacker. That DNA does not match Nowak, the defense attorney said.

The federal investigation found photos of the bizarre acts in the home. When police searched the Rochester Hills house, they also found a "cage and sex toys."

"There were photos of a guy coming from out of state to do the castrations on various people." Kaluzny said.

The prosecution on Friday offered evidence that it said shows that Nowak had sex with Moross after he was killed.

(Reporting by Bernie Woodall; Editing by Greg McCune)

Mochila insert follows.