A frail and ailing man admitted in court Thursday that he shot his love rival to death nearly 20 years ago.

Bernard Fred Rigby, 65, pleaded guilty to a charge of manslaughter before 3rd District Judge Vernice Trease. Rigby acknowledged that he killed Gary Feltch in 1990 because Rigby believed Feltch was a rival for the affections of Rigby's girlfriend.

Rigby's plea to the second-degree felony is part of a plea bargain that eliminates a trial that was set to begin July 13. Rigby originally had been charged with murder, a first-degree felony.

"Part of the reason for the plea is that his health is so poor," said Alicia Cook, spokeswoman for the Salt Lake County District Attorney's Office.

Rigby has had cancer and a stroke, must communicate with a mechanical voice box, uses a wheelchair and also has a number of other health problems.

Cook said prosecutors discussed the plea deal with members of Feltch's family, who found it acceptable.

"It was a satisfactory way to resolve the case from their perspective," Cook said.

She said prosecutors had some concerns with the cold case, but nonetheless were prepared to go to trial.

"With the combination of concerns and the state of the health of the defendant, it seemed like a plea to manslaughter was a very rational way to bring an end to the case."

Cook said that the district attorney's office agreed as part of the plea bargain to recommend that Rigby be sentenced as if the charge were a third-degree felony, which carries a possible sentence of zero-to-five years in prison, even though he pleaded guilty to a second-degree felony, which carries the possibility of a prison term of one-to-15 years behind bars.

However, the decision rests solely with Trease as to how she will sentence Rigby. The judge ordered a pre-sentence report and set Rigby's sentencing for Aug. 19.

"There is a statute that allows judges to take a plea on one level of offense and actually sentence them on one level down," Cook said.

Trease has said she would take that under advisement.

Steve Cook, a longtime friend of Rigby's, who retired after 20 years with the Salt Lake County Sheriff's Office, took the witness stand at a 2007 preliminary hearing and confessed that he had kept a terrible secret for Rigby for years.

Steve Cook testified that Rigby twice confessed to slaying Feltch because he was consumed with jealousy.

Steve Cook said he lied several times to law enforcement officials investigating the case to protect his friend, who Cook said "had gone through enough." Steve Cook said it saddened him to take the stand against his friend, but decided it was time that the truth came out.

e-mail: lindat@desnews.com