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INDIANAPOLIS – Fox59 News has learned that Marion County Prosecutor Terry Curry will announce a murder-for-hire indictment against one of the suspects in the Richmond Hill blast. Curry is expected to announce an additional charge against Mark Leonard during a 10:30 a.m. news conference on Thursday.

Jennifer and Dion Longworth were killed in the explosion, which investigators say was a plot to destroy a home and defraud an insurance company. Now, according to a source, the potential for bloodshed did not end there.

Homeowner Moncy Shirley; her boyfriend, Mark Leonard; and his half-brother, Bob Leonard, already face charges of murder and arson.

Investigators said the trio conspired with possibly one more person to blow up Shirley’s home on Fieldfare Way by opening up a gas valve on a fire place, filling the home with natural gas. Several hours later, a small metal tank placed inside a microwave oven set with a delayed timer exploded, setting off the blast that destroyed the Shirley home and damaged the homes of dozens of neighbors.

Just before Christmas, the Leonard brothers and Shirley were arrested and placed in the Marion County jail where they remain right now.

A source tells Fox59 news that jail investigators intercepted phone calls from Mark Leonard attempting to orchestrate a murder for hire scheme against a witness in the case. The prosecutor is expected to announce the results of a grand jury investigation Thursday.

Shirley and the Leonard brothers are due back in court April 10,when the judge begins taking a look at a 2014 trial date.  Each defendant faces the prospect of life without parole if convicted.