A Prince George's County Circuit Court judge yesterday acquitted the third and final defendant of all charges in the slaying of a Salvadoran immigrant in Laurel, angering Latino advocates who accused the state's attorney's office of not prosecuting the case vigorously.

After Steven Darby, 17, waived his right to a jury trial, his attorney asked Circuit Court Judge E. Allen Shepherd to acquit Darby. Darby faced seven charges, including first-degree felony murder, in the Sept. 4, 1998, assault of Gilberto Hernandez, 40, who was attacked as he and two brothers walked home from their restaurant jobs.

Two other defendants in the case were found guilty of offenses ranging from involuntary manslaughter to second-degree assault. During a brief hearing yesterday, Darby's attorney, Marcell Solomon, said that while his client was there, there was no evidence that he participated in the assault.

Shepherd agreed, dismissing all charges against Darby: first-degree premeditated murder, first-degree felony murder, second-degree murder, manslaughter, voluntary manslaughter and first- and second-degree assault.

"My heart and sympathy goes out to the Hernandez family, but the evidence in this case does not support some of the original allegations of what happened that night," Solomon said, referring to early news reports--later disproved by medical evidence--that Hernandez was stomped to death.

The Rev. Brian Jordan, a Franciscan priest who has helped the Hernandez family, sharply criticized State's Attorney Jack B. Johnson's prosecution of the case.

"From Day One, this case has been mishandled by Johnson," Jordan said. A staff aide for Johnson said he had no comment.

Jordan and other advocates for Hispanics have criticized Johnson for insisting that there was no clear motive for the attack, despite the conclusion of Laurel police that the assault began as a robbery. Gilberto's brother Juan, who was with Gilberto during the assault, testified at the first two defendants' trials that it began as a robbery.

Prosecutors offered no motive for the attack in their opening statements during the trials of the first two defendants, Cochise Iraun "Cody" Queen, 18, and Kellie Day Martin, 19. Only after Shepherd ruled there was enough evidence of a robbery to support a charge of felony murder did Assistant State's Attorney Fran Longwell ask jurors to convict them of murder in the commission of a robbery.

In October, Queen was convicted of involuntary manslaughter and two counts of second-degree assault. He has been sentenced to 15 years in prison. Martin was convicted this month of three counts of second-degree assault and is awaiting sentencing.

According to testimony, as many as seven attackers chased Tomas, Gilberto and Juan Hernandez as they returned home from their jobs. Gilberto's head fractured after Queen knocked him onto the ground, and Martin kicked him while he was down, according to testimony.