FORT WAYNE, Ind. (AP) — Indiana's attorney general said Thursday he would appeal a federal judge's order throwing out the guilty verdicts and death sentence of a southern Indiana man convicted of the fatal ambush of three people along a rural Warrick County road.

John M. Stephenson, 45, of Rockport, prevailed in his contention he didn't receive a fair trial when U.S. District Judge Theresa Springmann ruled Wednesday that he had ineffective counsel because his attorney didn't object to him having to wear a stun belt — a prisoner control device — in front of the jury that convicted him.

Warrick County jurors in May 1997 convicted Stephenson of killing John "Jay" Tyler and his wife, Kathy, both 29, and Brandy Southard, 21, all of Newburgh. Stephenson, who was a friend of Southard's boyfriend, has maintained his innocence.

Indiana Attorney General Greg Zoeller said Thursday the state will appeal the ruling either by asking Springmann to reconsider her ruling or going to the 7th U.S. Circuit Court of Appeals.

"The federal court's ruling this week is disappointing since we believe the Indiana Supreme Court ruled correctly when it denied Stephenson's petition for post-conviction relief on this very issue in April 2007," Zoeller said in a statement.

The Indiana Supreme Court rejected Stephenson's ineffective-counsel argument in an unanimous ruling. Indiana Chief Justice Randall Shepard, in a one-page concurring opinion, chided what he called the "rhetoric" of death-penalty appeals alleging ineffective counsel at trial.

However, Springmann, in her 26-page ruling, noted the state's concession that the Supreme Court had found Stephenson's attorney ineffective because there was no legitimate basis for the stun belt. She said wearing it prejudiced the jury against him.

"Due process mandates that John M. Stephenson is entitled to what he was denied: a trial without restraints" unless the state can show why they're necessary, Springmann said.

Prosecutors said Stephenson, on March 28, 1996, stole ammunition from Southard's home, then chased the Tylers' pickup — in which Southard was a passenger — to a rural intersection, where he emptied a 30-round assault rifle into the pickup, then stabbed the three.

The defense argued the prosecution's two main eyewitnesses lied about his role in the killings.

Warrick County Prosecutor Todd Corne, who tried Stephenson, said he was upset by the federal ruling because it was "based on something that wasn't substantial."

"The ruling wasn't based on any improprieties or insufficient evidence in the case," Corne said.