Indianapolis ? Police hunted on Friday for the killers who barged into a home and shot seven family members to death in the worst mass murder in Indianapolis in at least 25 years.

The bodies of three boys, ages 5 to 11, were found on a bed, and four adult relatives were discovered elsewhere in the house after the Thursday night robbery and massacre that rocked the working-class neighborhood.

Police said the attackers – a witness reported seeing three or four men run out of the house – were armed with assault rifles.

A search of a home for one of the suspects turned up empty after police officers fired tear gas and broke down a door Friday night.

Police said the 28-year-old suspect grew up in the area and had returned last fall after getting out of prison on drug and weapons charges.

“He’d gone there to rob the home and decided while he was there to execute everybody at the same time, unfortunately,” Sgt. Matthew Mount said.

Police said they could not immediately tell whether anything was taken from the neat, 1 1/2-story home.