A Prince George's County Circuit Court jury yesterday acquitted a Laurel teenager of first-degree felony murder in a highly publicized attack on a Salvadoran immigrant but found him guilty of three counts of second-degree assault.

After a 2 1/2-day trial, the jury deliberated for nearly three hours before reaching its verdict on Kellie Day Martin, 19. Martin, who was jailed shortly after the fatal Sept. 4, 1998, assault on Gilberto Hernandez and released on bond in May, was ordered into immediate custody by Circuit Court Judge E. Allen Shepherd.

Hernandez, 40, was attacked in Laurel by a group of teenagers as he walked home from work. He was chased and knocked to the concrete, suffering a skull fracture. Two younger Hernandez brothers escaped the attackers, one on bicycle, one on foot.

Prosecutors alleged during the trial that Martin inflicted a "soccer-style kick" to Gilberto Hernandez after he had been knocked to the ground and rendered unconscious by another attacker. Prosecutors alleged that Martin's kick caused a second skull fracture. Defense attorneys said Martin only nudged the victim with his foot to see whether he was badly hurt.

Martin could be sentenced to a maximum of 10 years in prison for each count of second-degree assault. State sentencing guidelines call for a sentence of probation to two years in prison, his defense attorneys said. Shepherd scheduled sentencing for Dec. 16.

Despite the guilty verdicts on the assault charges, a Latino advocate who has been sharply critical of the way State's Attorney Jack B. Johnson has prosecuted the case accused Johnson of "throwing" the Martin prosecution.

"From the beginning, the prosecutor's office was throwing this case, and defense attorneys did what they should. They stayed out of their way," said Bill Stagg, director of the county's Hispanic Resource Center. A member of Johnson's staff said the prosecutor will not comment until after the third defendant in the case is tried.

Stagg noted that the opening statement by Assistant State's Attorney Fran Longwell, who prosecuted Martin, made no mention of a robbery attempt, which one of the surviving Hernandez brothers alleges sparked the attack. In interviews over the last year, Johnson has repeatedly said there was no clear motive for the attack and no credible evidence of a robbery attempt.

To obtain a first-degree felony murder conviction against Martin, prosecutors needed to prove that the fatal attack occurred during the commission of a robbery.

Felony murder was the most serious charge Martin faced. On Tuesday, on a motion by Assistant Public Defender David Harding, Shepherd dismissed most of the major charges: first-degree premeditated murder, second-degree murder, manslaughter, involuntary manslaughter and first-degree assault.

Martin is the second teenager convicted in the case. Last month, a Circuit Court jury convicted Cochise Iraun "Cody" Queen, 18, of involuntary manslaughter and two counts of second-degree assault. Shepherd sentenced him to 15 years in prison. A third teenager, Steven Darby, 17, is scheduled to go on trial Nov. 29.