Deadly explosion in Indianapolis was suspects’ third try, affidavit says

A fourth suspect in a deadly explosion that ripped through an Indianapolis neighborhood in 2012 had helped with a skittish effort to set a house on fire and collect insurance money, according to a probable cause affidavit released Thursday.

Gary Lee Thompson, 44, was charged Thursday with two counts of murder, a count of conspiracy to commit arson and 46 counts of arson.

The suspects tried and failed twice to burn the house before succeeding on the third try, according to the probable cause affidavit. The Nov. 10, 2012, explosion killed Jennifer Longworth, 36, and her husband, John “Dion” Longworth, 34, who lived next door. It also destroyed five homes and damaged dozens of others so badly that officials ordered their demolition.

Prosecutors say Thompson, along with homeowner Monserrate Shirley, her boyfriend Mark Leonard and his brother Bob Leonard Jr., intentionally leaked natural gas into Shirley’s house and then used a programmable microwave to trigger the blast.

Shirley, 49, agreed this month to plead guilty to two felony counts of conspiracy to commit arson, according to Peg McLeish, a spokeswoman for the Marion County prosecutor’s office. In exchange, McLeish said, Shirley agreed to cooperate with investigators and provide information in the case against the Leonard brothers and others.

This month, Thompson told police that he worked for Mark Leonard for several years and knew of Leonard’s plan to use natural gas to start a fire at Shirley’s home, the affidavit released Thursday says.

According to the affidavit, Thompson said Leonard offered to pay him $5,000 to pour gasoline in Shirley’s home and start the fire the weekend of Oct. 27, 2012, but Thompson said he didn’t follow through with setting the fire because he was afraid.

Shirley told police that Thompson and Leonard then “worked on the house in an effort to set a fire for the following weekend,” working on the thermostat and sealing off the fireplace to prevent gas from escaping, the affidavit said.

Thompson said Leonard asked him questions about natural gas; for example, “specifically about how much natural gas it would take to fill the house and reach a candle burning in the upstairs bathroom,” the affidavit said.

It also said Thompson admitted to advising Leonard about what kinds of thermostats would create sparks and to being involved in a discussion with Leonard about how a microwave could be used as an ignition source if metal was put inside and the microwave was programmed to start at a later time.

The Leonard brothers each face two counts of murder, a count of conspiracy to commit arson and multiple counts of arson. Mark Leonard also faces a murder-conspiracy charge. Prosecutors said that while in jail, he tried to hire a hit man to kill a key witness against him in the case.

McLeish said prosecutors expected the Leonards’ cases would be among the most challenging the agency has faced, with more than 200 witnesses lined up for each man’s trial.

Times staff writer Christine Mai-Duc contributed to this report.

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