GARFIELD HEIGHTS, Ohio (WJW) – The State Fire Marshal’s Fire and Explosion Investigative Bureau has determined that a Garfield Heights home explosion that killed three people last month was caused by the manufacturing of explosives.

Firefighters responded to the home at 4930 E. 81st St. on June 12 upon reports of an explosion. Firefighters found only debris when they arrived. The adjacent homes had caught fire. Three people inside the home were initially reported missing.

Investigators say firefighters located remnants of cardboard tubes, consistent with the manufacturing of explosive devices in the basement of the home. Investigators also found fuses, equipment and chemicals associated with the manufacturing of explosives.

State Fire Marshal Forensic Lab Bureau Chief Chad Wissinger said, “The materials recovered from the scene are used in the manufacturing of M-series type explosive devices, which contain higher amounts of explosive powders than what is typically found in consumer-grade fireworks.”

Fire investigators say the official cause will remain undetermined pending the final report from the Cuyahoga County Medical Examiner.

There was no evidence of a gas leak.

The bodies of 64-year-old Donald Malinowski, 57-year-old Gerald Bateman and 37-year-old Cassandra Bateman were found in the rubble of the home.

The Fire and Explosion Investigative Bureau will hold an update on the explosion later today. FOX8.com will stream it live.