INDIANAPOLIS, DEC. 10 -- The body of a 5-year-old girl was found today in the wreckage of an apartment building leveled in an explosion apparently caused by a natural gas leak at Fort Benjamin Harrison.

Seventeen people were injured, four critically, in the blast Sunday night. Base residents criticized the Army for failing to provide adequate warning of the danger of the gas leak.

The explosion destroyed a four-unit apartment building in Harrison Village and heavily damaged a second building, officials said. It occurred hours after fire authorities arrived to investigate a gas leak at another building in the complex, which housed enlisted personnel. That one was being evacuated when the blast went off several hundred feet away, authorities said.

Marion County Deputy Coroner Charles W. Green said he could not conclusively identify the dead child. Base officials said there was little doubt that she was a 5-year-old girl reported missing earlier. Her identity was not released.

As fire officials investigated the leak, military police notified some residents that their gas was turned off and that they might not have heat until today, said Sgt. Clayton R. Glass, who first reported the leak behind his quarters.

"We all knew what it was as soon as we heard it. . . . We all smelled gas outside, it was so thick," said Victoria Glynn, a resident.

She said military police asked residents whether they wanted to be evacuated to a hotel or stay in their homes. "We were never told there was possible danger," she said.

Joan Adams, another resident, said military police who knocked on her door told her "there was no danger for us to stay here."

"We don't know exactly what caused the explosion," said Dan O'Brien of Citizens Gas Co., which supplies gas to the base-operated system.