A jury convicted an Indianapolis man of murder, arson and insurance fraud Tuesday for his role in a house explosion that decimated a subdivision nearly three years ago, killing a couple living in the neighborhood.

The jury found 46-year-old Mark Leonard guilty of all counts against him, including murder and felony murder. Prosecutors alleged Leonard was the mastermind behind the explosion, plotting with his then-live-in girlfriend Monserrate Shirley and his half brother Bob Leonard to blow up the home for $300,000 in insurance.

Shirley accepted a plea deal and testified against her former boyfriend. Bob Leonard and two others are awaiting trial.

Defense attorney John Shircliff told jurors during closing statements that Shirley was a "master liar" and wasn't a credible witness.

During opening statements in the monthlong trial, defense attorney Diane Black described the explosion that damaged or destroyed 80 homes as "a stupid and selfish insurance fraud that went horribly wrong."

Prosecutors said in closing arguments that testimony showed Leonard wanted more than a small fire after two previous unsuccessful attempts to burn down the house the previous two weekends. They said he filled the house with natural gas and then poured gasoline in two rooms to make sure the third try didn't fail, using a canister in a microwave to ignite the blast.

Marion County Deputy Prosecutor Denise Robinson said Leonard and the others made sure they, Shirley's daughter Brooke and her cat Snowball were nowhere near the house at the time of the explosion "because of the probability of what would happen" after removing safety valves, allowing natural gas to pour into the house.

Shirley, who accepted a plea deal and agreed to testify against her former boyfriend, said Leonard told her he was only planning a small fire. She said at first she dismissed it as a "crazy" idea. But she said he wouldn't take no for an answer and he told her no one would get hurt.

Testimony included neighbors describing being awakened by what some described as the loudest noise they ever heard, with some believing the explosion occurring in their own homes. Others testified they thought a plane had crashed into the neighborhood. Firefighters gave emotional testimony about trying to rescue John "Dion" Longworth, whom they could see in the basement through a hole and one firefighter could grab his arm, but they couldn't pull him out before he was overcome by flames.

"He was saying, 'It's so hot, so hot. Get me out! Please, get me out!" Indianapolis firefighter Richard Shirven said.

The coroner ruled Dion Longworth died of inhaling hot gases and soot and had burns over 90 percent of his body. Jennifer Longworth died of blast injuries that caused almost instant death.

Prosecutors told jurors they don't believe Leonard intended to kill the Longworths but should have known that by using a combination of natural gas and gasoline that he should have known the possibility of someone dying.

Leonard was charged with two counts of murder, two counts of felony murder, 12 counts of arson involving bodily injury, 34 counts of arson with no bodily injury, two counts of conspiracy to commit arson and one count of conspiracy to commit insurance fraud.

The prosecution presented 169 witnesses during the trial while the defense called one, an Indianapolis police detective who described how sincere Shirley seemed when telling him two days after the explosion she didn't know how it happened.

The defense laid the groundwork for a possible appeal by making several requests for mistrials, including one over alleged prosecutorial misconduct that led St. Joseph County Superior Court Judge John Marnocha to delay testimony for a day. The most recent request came Monday, when Shircliff argued that Robinson had mischaracterized the testimony of an agent from the Bureau of Alcohol, Tobacco, Firearms and Explosives as evidence during her closing statement.