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ASHTABULA, Ohio --

Investigators believe a meth lab may be the cause of a deadly fire inside a local nursing home.

Around 8:30 p.m. Sunday, firefighters were called to the Parkhaven nursing home in Ashtabula. A room on the second floor was on fire. Firefighters say when they arrived, staff members were already trying to get residents out of the building.

"They encountered pretty heavy smoke conditions, and the fire was still contained to the room. The sprinklers did a pretty good job holding the fire in the room of origin," said Ashtabula Fire Chief Ron Pristera.

Shawn Warrens, 31, was killed in the fire. He was not a resident of the facility. Four other people -- three residents and one non-resident -- were injured.

"There were people who were treated and released, there were people who were transported by ambulance, and then there was one person who had some pretty significant injuries," said Pristera.

Once the smoke cleared, and investigators started looking into what caused the fire, they were stunned by what they found.

"When we first started to get the indications, we all sort of looked at each other and went, 'You know, are we seeing what we think we're seeing?' " said Pristera.

The cause, according to fire investigators, was a secret methamphetamine lab in one of the rooms.

"Pretty significant damage to the room of origin, water damage below, some light smoke damage," said Pristera.

The chief says investigators are still trying to determine who created the meth lab, creating a deadly danger for residents and employees.

"This is unchartered territory for us, and I imagine about everybody else," he said.

A spokeswoman for the nursing home had no comment.