NEW YORK, AUG. 18 -- A young black man who escaped a mob of white teen-agers in the fatal Howard Beach racial-attack case pulled a knife on the youths before fleeing and lied about it to a grand jury, authorities said today.

Prosecutors said the revelation that Timothy Grimes pulled a knife during the attack in Queens last December will have no impact on the case because Grimes was being approached by a bat-wielding mob.

But defense attorneys for four teen-agers due to stand trial for murder and manslaughter said the revelation changes the case from a racial incident to a "confrontation."

Grimes was one of three blacks attacked near a Howard Beach pizzeria. One of them, Michael Griffith, 23, was killed by a car when he ran onto a highway to escape.

Grimes, now 20, and Cedric Sandiford, 36, told police they were unarmed during the attack. l incident; you have a confrontation.

"If there are intruders in your neighborhood and they show they are dangerous by showing weapons, then the people who live there have to worry about their safety and the safety of others. Then the events become understandable and the color of their skins becomes insignificant."

AP-NY-08-18-87 2206EDT