Two of the boys pleaded guilty to robbery and were sentenced to 16 and 17 years in prison. A third, who was 14 at the time of the crime and admitted to striking the fatal blow, pleaded guilty to second-degree murder and was sentenced to seven years in prison and lifelong parole. A fourth, Jamel Murphy, 18, is expected to be sentenced to 11 years, in exchange for having agreed to testify against the others.

Ms. Royster's lawyer, Robert DiDio, had tried to persuade prosecutors to offer his client a much lighter sentence than 17 years. He had argued that because of her role in the crime -- ordering the food from her cellular phone -- and her history of mental illness, she should have been spared the prospect of spending much of her adult life in prison.

Her grandmother, Anastacia Brown, who raised Ms. Royster from age 3, said: ''She got the worst deal of them all, in spite of the fact that the district attorney had all her medical and psychiatric records and the fact that she never laid a hand on the deliveryman. There should have been a little more understanding and compassion.''

But under criminal law, Ms. Royster's role -- luring Mr. Liu to the house -- makes her as responsible as the boy who admitted striking him with the brick. And if she had gone to trial and the prosecution had convinced a jury that she knew of a plan to harm the deliveryman, she could have been convicted of murder.

''The defendant has admitted that she made the phone call to the restaurant for a food delivery and was part of a plan to rob the deliveryman,'' District Attorney Richard A. Brown of Queens said yesterday. ''The defendant has acknowledged her role in the vicious and brutal crime. The 17-year prison sentence is just punishment.''