Chesapeake (Virginia), Dec 04: Sniper mastermind John Allen Muhammad was suspected of lobbing a grenade into another soldier's tent during the gulf war and once threatened to "slaughter'' a superior, a former platoon sergeant testified. Kip Berentson, 48, said yesterday at the trial of Muhammad's alleged accomplice that no one was wounded in the 1991 grenade attack and no charges were brought, but Muhammad was transferred to another platoon.

"I considered him a threat,'' Berentson said.

Lawyers for 18-year-old sniper suspect Lee Boyd Malvo are pursuing an insanity defense, contending Muhammad brainwashed the boy and turned him into a killer.

Berentson read a portion of Muhammad's military record in which a supervisor wrote that he counseled Muhammad for poor performance and Muhammad answered with a threat: "brother to brother, back off or you'll be the first who will be slaughtered.''

Earlier yesterday, circuit judge Jane Marum Roush barred Malvo's lawyers from introducing a letter in which the teenager supposedly pleads for help and warns he is a "ticking time bomb.'' Roush ruled the letter was hearsay. Bureau Report