A powerful explosion blew the top off a house where a registered sex offender described as acting paranoid had rented a room and appeared to have been making bombs, deputies said Tuesday.

Investigators found a body in the rubble Tuesday morning, Pierce County sheriff's Detective Ed Troyer said. They believe they know the person's identity but did not release details.

He said the couple who owned the house told authorities late Monday they had returned from a trip and found their tenant was acting strangely and making explosive devices.

Troyer said the man was in the kitchen when deputies arrived. He quickly grabbed bottles and a duffel bag containing what the deputies recognized as components of explosive devices and ran upstairs, where he turned on loud music.

Deputies hustled the owners out of the house, and about 10 minutes later it exploded.

"He either accidentally or intentionally set the explosion off, which took the whole top floor off of the residence and engulfed the house in flames," Troyer said.

"This wasn't a little explosion. This was the real deal," he said.

Troyer said the tenant was a 26-year-old registered sex offender.

"He's had some issues with law enforcement over the years," Troyer said, "and actually, from what we're learning, had a rough week leading up to this ... paranoid, changing locks and doing some strange stuff, according to witnesses," he said.

Puyallup is about six miles southeast of Tacoma.