A 21-year-old Arlington man who had threatened suicide was found shot to death in his house last night by members of a police SWAT team who broke in after surrounding the residence for several hours of tense waiting.

An Arlington police spokesman said the victim, identified as Donald Earl Atwood of 1614 s. Randolph St., shot himself in the head with a 30-06 rifle.

Police said Atwood was on probation in connection with a federal charge stemming from an explosion that blew up a dugout at the Wakefield High School athletic field in Arlington.

Police spokesman Tom Bell said Atwood called his probation officer about 5 p.m. yesterday to say he was going to kill himself.

When police arrived in the neighborhood they were told that a neighbor heard what might have been furniture being moved inside Atwood's house, suggesting he may have been barricading himself inside.

Houses on each side of the Atwood residence were evacuated, according to the spokesman, and police tried to make contact with Atwood by telephone and by use of a bullhorn.

Atwood was alone in the house at the time. Police said his mother was on vacation and traveling in Florida.

After efforts to speak with Atwood failed, the SWAT unit, led by Arlington Police Chief William Stover, broke into the house and discovered Atwood's body in the bathroom.

The spokesman said he did not know of a motive for suicide A note was found in the house but its contents could not be learned.