Discuss as:

Three charged with murder, arson in Indianapolis house blast

Prosecutors announced charges Friday against three people in connection with a house explosion in Indianapolis last month that left two dead and destroyed dozens of homes.

Mark Leonard, Monserrate Shirley and Bob Leonard Jr. were each charged with two counts of murder and multiple counts of arson, according to authorities. The Nov. 10 explosion in the Richmond Hill neighborhood in south Indianapolis happened at Shirley's residence and ignited a fire at the house next door, killing neighbors Jennifer Longworth, 36, and Dion Longworth, 34.

Prosecutors said Shirley; her boyfriend, Mark Leonard; and Mark's brother Bob Leonard Jr., were all taken into custody Friday morning, the Indianapolis Star reported. Officials say Shirley and Mark Leonard had arranged to be at a casino the night of the explosion, according to Reuters.

The blast also caused injuries to 12 other people in Richmond Hill, prosecutors said. Marion County Prosecutor Terry Curry said at news conference that 33 homes had to be demolished, according to Reuters.

Previous story: Indianapolis house explosion being investigated as homicide

"We have to acknowledge that we are helpless to alleviate the pain and anguish of such innocent victims and their families," Curry said. "However, what we as a public safety community can do and must do is devote our best efforts to see that justice is served on behalf of those victims."

Authorities allege the three charged had released gas into the house and used a microwave oven set on a timer to ignite the gas, according to the Star. Prosecutors say they wanted to cash in on insurance payments and Shirley had recently increased her house insurance to $300,000, the newspaper reported.

An initial hearing date for the case has not been set.

The complete list of charges from the Marion County Prosecutor's Office:

Mark Leonard, Monserrate Shirley and Bob Leonard Jr. each charged with the following:

-Felony Murder (two counts)
-Conspiracy to Commit Arson, Class A Felony (one count)
-Arson, Class A Felony (12 counts)
-Arson, Class B Felony (33 counts)

Both Mark Leonard and Monserrate Shirley are each charged with an additional count of Conspiracy to Commit Arson, a Class B Felony.

Reuters contributed to this report.

More content from NBCNews.com:

Follow US news from NBCNews.com on Twitter and Facebook