LAFAYETTE — In response to a prosecutor’s challenge, 15th Judicial District Judge Edward D. Rubin changed Jerry Steinle’s three-year suspended manslaughter sentence Thursday to one year of home incarceration.

Rubin found Steinle, 62, guilty of manslaughter in August in connection with the December 2009 shooting death of David Trahan, 40.

In a court motion, Prosecutor Keith Stutes argued that people convicted of crimes of violence, such as manslaughter, are to be denied the benefit of suspended sentences.

In response, Rubin altered the sentence Thursday to one year of home incarceration with credit for the 62 days Steinle had previously served.

“I believe it to be a lenient sentence under the circumstances,” Stutes said after Rubin’s ruling.

Steinle’s attorney, Thomas E. Guilbeau, said he is appealing the verdict.

“We are expecting the verdict to be reversed,” Guilbeau said.

During his trial, Steinle, a retired helicopter pilot, testified he shot Trahan three times in self-defense after Trahan struck him across the face during a confrontation under Steinle’s carport on Rena Drive.

The encounter occurred after Trahan had written “Jerry has sex with little boys” across Steinle’s door.

That encounter followed a separate incident in 2005 when Trahan was arrested for spray-painting the word “pedophile” across the roof of Steinle’s home.

Police have said they have no record of any such complaint against Steinle.

Melissa Trahan said her ex-husband told her that Steinle molested him over eight years when he was a boy living next door.

She said David Trahan was “only trying to protect other boys from going through the same thing he went through.”

She said David Trahan was not armed during his encounter with Steinle.

“I’m glad that Lafayette knows what kind of man Steinle is,” she said.

When handing down his verdict last month, Rubin said the force Steinle used was not reasonable.

Rubin said that while he was not privy to what had occurred in the past, testimony given during the trial indicted Trahan had been suicidal, his behavior had been erratic and his blood alcohol content was well above the legal limit.

The judge said it appeared that Trahan had attempted to “engage in self-help by taking the law in his own hands.”