Indianapolis Blast Being Investigated as Homicide

The probe into a massive explosion earlier this month in Indianapolis that killed two people and damaged dozens of homes is now an active criminal homicide investigation, with authorities saying they believe the blast was caused intentionally, ABC News has learned.

At a meeting this evening at the Southport Presbyterian Church to update residents of the Richmond Hill subdivision where the blast occurred, Marion County prosecutor Terry Curry said the criminal homicide investigation is ongoing.

"While the fire investigation has been progressing, there has been a parallel investigation, not solely focusing on the cause of the explosion but focusing on individuals who may have been responsible once accidental causes were eliminated," Curry said. "That investigation has consisted of numerous interviews with various individuals as well as execution of a number of search warrants and is being conducted jointly by the [Indianapolis Metropolitan Police Department] and the [Marion County Prosecutor's Office]."

The ATF offered up to $10,000 for information that leads to an arrest in the case.

The explosion in the subdivision just south of the city on Saturday, Nov. 10, killed John and Jennifer Longworth. Their funeral was held earlier today.

Much of the attention since the explosion has centered on Monserrate Shirley and her boyfriend Mark Leonard, who lived at the house in the center of the blast area.

John Shirley, who owns that house but now lives elsewhere, told ABC News two days after the blast that he believed that his ex-wife, who still lives in the house, was to blame for the explosion.

Shirley claimed he knew that the furnace in the house was broken and had not been fixed properly, if at all.

"If I were to suspect anything, that's where the problem was," said Shirley, who noted that his ex-wife Monserrate Shirley had a "protective order" against him. However, Shirley said he did not believe his ex-wife would have caused the explosion intentionally.

"I don't think so, because there was no real reason to," Shirley said. "I pay a thousand dollars a month for one kid because she had a lawyer and I did not, so she has more than enough money. At one point the house was slipping into foreclosure. Last spring she had a buyer but she chose not to sell. We were in some bankruptcy but that's pretty well cleared up."

Monserrate Shirley and Leonard were reportedly visiting a casino at the time of the blast.