Lawyers for an Army staff sergeant accused of fatally shooting a police officer working her first shift are fighting prosecutors' efforts to bring the sergeant's 11-year-old son in front of a grand jury.

Authorities say Ronald Hamilton, of Woodbridge, about 22 miles southwest of Arlington, shot and killed his wife, Crystal, in a Feb. 27 domestic dispute. They say he then fatally shot Prince William County officer Ashley Guindon, who responded to Crystal Hamilton's 911 call for help. Two other officers, Jesse Hempen and David McKeown, were also shot responding to the scene but survived.

Hamilton's son witnessed some of the events. He has given a statement to police but prosecutors also want him to testify in front of a grand jury later this month.

Ronald Hamilton's family in South Carolina has custody of the boy. Hamilton's lawyer said forcing the boy to testify could be emotionally difficult for him.

"The child has already spoken to police," said Hamilton's lawyer, capital public defender Edward Ungvarsky. "It'd be traumatic for him to come."

Prosecutors said Ungvarsky has no standing to argue about what is in the boy's best interests. Judge Lon Farris agreed and rejected Ungvarsky's efforts to block the testimony at a hearing Thursday, but he left the door open for Ungvarsky to file a formal written motion renewing his argument.

Commonwealth's Attorney Paul Ebert said he has been forced to use out-of-state subpoenas to bring Ronald Hamilton's family and the 11-year-old son in front of the grand jury. "Let me put it this way: They ain't coming voluntarily," Ebert said after the hearing.

The judge on Thursday also set a June 2017 trial date for Hamilton's case, where he could possibly be sentenced to death. The date was a compromise that fully satisfied neither prosecutors, who wanted a 2016 trial date, nor defense lawyers, who wanted more time to prepare their case.

Hamilton has confessed to the shootings, according to court records. His lawyer says Hamilton's mental health is in question and that he returned from two tours in Iraq as a "Psychologically damaged and mentally impaired" individual.