INDIANAPOLIS (ABC News) -- As questions remain about the deadly November house explosion in Indianapolis that killed two people and destroyed 33 homes, prosecutors say the man facing trial for the deed is now at the center of an attempted murder-for-hire plot.
Mark Leonard, his girlfriend Monserrate Shirley -- who owned the home that exploded -- and his brother Bob Leonard are all facing murder and arson charges after Shirley's home exploded Nov. 10 in Indianapolis' Richmond Hill subdivision, killing her school teacher neighbor next door Jennifer Longworth and her husband, John.
Investigators believe the house was blown up in a plot to collect in the recently-increased $300,000 insurance policy that covered the personal property in the home.
Now, from Marion County jail, Mark Leonard is accused of phoning an undercover federal agent posing as a hit man, according to Marion County Prosecutor Terry Curry.
"Mr. Leonard stated that he wished to arrange for the death of a witness in the explosion case," Curry said at a press conference Thursday.
Jailhouse calls are monitored and recorded, as indicated by a sign above the phone alerting prisoners to this fact. Investigators say that despite this warning, Leonard used the jailhouse phone to plan the murder of a witness only identified as "M.D."
"It is further alleged that Mr. Leonard drew a map for directions to that target's house and signed an agreement to pay $15,000 upon the death of 'M.D.'" Curry said.
Leonard had no idea at the time that an undercover agent was in on the plot.
"On March 13, Mr. Leonard placed a call to the undercover agent in which Mr. Leonard again confirmed his intent to have 'M.D.' killed," Curry said.
Prosecutors say Leonard offered the hit man a $5,000 bonus if he made the witness' killing look like a suicide. Leonard also allegedly had wanted the witness to call 911 and recant his statement to investigators before his death.
In December, Curry said that as soon as investigators began poring over the remnants of Shirley's home, they noticed that the microwave oven had been blasted out from the inside. A small canister found in the kitchen may have been inside the microwave, but authorities said it was being tested for evidence of flammable contents.
In addition to the murder and arson charges, Leonard has now also been charged with one count of conspiracy to commit murder, Curry said. In February, Curry said that he would seek life without parole for Shirley and the Leonard brothers.