This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

INDIANAPOLIS, Ind. (Jan. 20, 2015)– The woman who owned the house that blew up in 2012, rocking the south side and killing her neighbors, has agreed to plead guilty to two counts of conspiracy to commit arson and testify against the ex-boyfriend investigators call the brains of the murderous scheme.

Monserrate Shirley, 49, signed a plea agreement that was filed in Marion Superior Court 3, promising to tell prosecutors, judges and juries all she knows about the Richmond Hill blast and to go to court against anyone involved, even an unindicted mystery co-conspirator.

“From a prosecutor’s perspective it means we have direct evidence of the crime,” said Deputy Prosecutor Denise Robinson who hammered out the deal with Shirley’s high-profile defense attorney James Voyles. “In other words, we have someone who was on the inside, who was a party to making certain observations, overhearing certain statements and she is now cooperating with the State.”

By pleading guilty to two felony counts of conspiracy, Shirley faces a potential 20-50 years in prison with a presumptive term of 30 years, though the judge would reserve the option to sentence the single mother to a suspended sentence, probation and time served.

That possibility angered at least one neighbor who lost his home.

“There are 52 counts that were released, including the demolition of at least 33 homes, and she could walk out with nothing but time served,” said Tony Burnett whose home across the street from 8349 Fieldfare Way was destroyed. “That doesn’t sound right to me in any way, not to mention the death of two people.”

Jennifer and Dion Longworth, Shirley’s neighbors, were killed in the fire and blast.

“Everything we’ve been hearing all along was that this case was strong enough, that they felt they had strong convictions on all three, and if they felt that strong about the case, I don’t understand why 54 counts were released.”

Under the plea agreement, Shirley will not face murder, multiple arson conspiracy and two insurance fraud charges.

The Marion County Prosecutor’s Office also rescinded its attempt to sentence Shirley, if convicted, to life without parole.

“Thus far the information she’s provided has been consistent with what we know about the investigation,” said Robinson. “We’ll continue to corroborate it. If at any point any information she gives us is not truthful then we certainly have no interest in moving forward with her testimony and we would not move forward with the plea.”

Voyles told Judge Shelia Carlisle that his client has talked extensively to prosecutors and has even more information to share, specifically regarding a fourth unnamed co-conspirator.

“The identification of other individuals has already commenced,” said Robinson. “We have an investigation started in regard to other individuals. Whether those other individuals fully participated, partially participated, or can provide additional information is yet to be known.”

Witnesses told police they saw Bob Leonard Jr. and another man enter the house his brother, Mark Leonard, shared with Shirley on the afternoon of Nov. 10, 2012, some ten hours before the explosion that damaged dozens of homes, caused $4 million in losses and killed the Longworths.

Mark Leonard and Shirley were at a Lawrenceburg casino waiting to hear news of the blast and fire according to prosecutors.

“I don’t think she was misled by any stretch of the imagination except perhaps as it concerns the level of whether it was going to be a fire or explosion, the nature of what might happen, maybe she didn’t understand or fully appreciate that,” said Robinson, “but I don’t believe she was misled. I believe she knew what was going to happen.

“She made arrangements for them to stay elsewhere, she made arrangements for (her daughter) to stay elsewhere and she made arrangements for the cat to stay elsewhere.”

Voyles told the Court that Leonard had tried twice unsuccessfully in the weeks prior to the explosion to destroy the house and both times Shirley participated in the planning and execution of the home’s evacuation.

“I personally suspect there may be more involved in this just from a little bit that I know that I shouldn’t say, but I suspect that there may be more involved in this,” said Burnett.

Voyles said that Leonard had plotted for nearly a year to commit insurance fraud to collect $300,000 in proceeds to bail Shirley out of financial trouble.

As the attorney known for his ability to strike bargains with prosecutors on behalf of his clients detailed the plot that ruined so many lives, both Shirley and neighbors in the courtroom choked back tears and appeared glum.

When Shirley was asked why she was pleading guilty, the admitted arson conspirator answered, “Because I am guilty.”

Shirley’s agreement to cooperate with investigators may delay this summer’s scheduled trial of Mark Leonard and the yet to be determined trial of his brother.

Leonard is set to go on trial in South Bend in a change of venue June 4 during what is expected to be at least five weeks of testimony and hearings.

Defense attorney Jeff Mendes, who is not connected to this case, told FOX59 News that prosecutors and the defense may seek a delay to debrief Shirley in depositions or track down any other suspects her cooperation may reveal.

PHOTOS: Richmond Hill explosion