Alexandria police exchanged gunfire with the owner of a small manufacturing firm early yesterday in an incident that the businessman said began when he believed he was being stalked by burglars.

James H. Nachod, 39, said he was working in his office at Wood Techniques, 3127 Colvin St., at about 2 a.m. when he heard noises outside his door. When he peered out from behind the door, he said, he saw figures, and fearing he was being burglarized, fired his handgun through the door.

In moments .38-caliber fire was returned from police revolvers. No one was injured. Police arrested Nachod and charged him with attempted felonious assault.

Alexandria police spokesman Kathy Salvas said a police officer on routine patrol had checked the door of Wood Techniques earlier and found it locked. When he noticed it was ajar about 2 a.m., he called for help and was joined by two other officers, Salvas said. The shooting broke out as the three approached the firm, she said.

Nachod, who lives at 4961 Americana Dr., Annandale, was free under $1,000 personal recognizance bond. He said in an interview yesterday his business had been burglarized twice and police had advised him to buy a handgun for protection.

"When I looked out from that bright office light, all I could see were dark figures moving." He said that after he fired through the door, he was reassured by the sound of the answering .38-caliber gunfire.

"When I heard those .38s, I knew they were the good guys," Nachod said. "I laid on the floor and started shouting, 'Owner! owner!' "

"I wish they had said something like, 'We are the police,' " he added.