Indianapolis authorities are now treating the explosion that destroyed homes and killed two neighbors as a homicide. Police say they are investigating a white van that was seen in the neighborhood before the explosion.

On Nov. 10 a huge blast destroyed dozens of homes and killed a couple, Dion and Jennifer Longworth, reports the Indianapolis Star. The explosion occurred in Richmond Hills, a subdivision of Perry Township near Indianapolis.

Gary Coons, chief of the Indianapolis Department of Public Safety’s Homeland Security division, said, “At this time we’re here to inform you that we’re turning this into a criminal homicide investigation,” reports the Star.

Marion County Prosecutor Terry Curry said authorities are offering $10,000 for more information about the explosion, reports The Associated Press. He said police are investigating a white van that was seen in Richmond Hill before the explosion.

Moncy Shirley and her boyfriend, Mark Leonard, whose home was at the center of the explosion, were at a casino at the time, reports Fox59 News. Insurance companies are going through the debris in order to assess damages and possible causes for the explosion. According to Fox59 News, the explosion caused $4.4 million in damages while Indianapolis Star reports that 81 homes were damaged.

According to reports, the blast was a natural gas explosion.

The insurance investigation, along with the fire investigation, has been going on for a week, notes the AP, but the criminal investigation is the most recent development. The Marion County Prosecutor's Office and the Indianapolis Metropolitan Police Department have been conducting interviews and have issued search warrants. Based on the information gathered so far, Coons and Curry have reason to believe the explosion may be a homicide case.

According to Shirley, her house had no gas problems and she had no possible explanation for the explosion, reports Indianapolis Star. The newspaper does note that Shirley and Leonard have had several run-ins with the law and that Shirley had put the home up for sale.

Indianapolis Mayor Greg Ballard said, “There is a search for truth and there is a search for justice," reports the AP.