HOUSTON -- A 12-hour SWAT standoff in northwest Harris County ended early Thursday when the man holding officers at bay killed himself, officials told KPRC Local 2.

Harris County Precinct 4 deputy constables went to the home in the 21100 block of Covington Bridge Drive Wednesday afternoon to serve eviction papers.

James Hahn, 39, refused to come out, lit fires inside the home and pointed guns at officers, investigators said.

The Houston Police Department's SWAT officers were called in to negotiate with Hahn. Hahn threatened officers over the telephone, police said.

Police said Hahn had recently told deputies that they would not take him out of his home alive.

"We believe this particular individual did not want to go peacefully and was going to be here for the long haul," HPD Capt. Bruce Williams said. "He stated to the SWAT officers that we knew what he did for a living, so we knew what he was capable of doing and that he had chemicals inside the home."

Hahn was a chemist who was dealing with money and drug problems, police said. Neighbors said he was quiet and recently divorced.

Investigators said Hahn went into a room at the back of the home and fired shots at them when they tried to use a pole camera to look inside.

"The suspect then began to throw what we believe were Molotov cocktails out at the officers and light other fires," Williams said.

Detectives said Hahn then fatally shot himself.

Officers went into the home and found Hahn wearing a gas mask and a chemical suit. Guns and explosives were found in the home, investigators said.

Police said Hahn had boarded up all the windows and had placed surveillance cameras around the outside of the house.