Lawyers for a man accused of murdering a Montgomery County police officer and a security guard are claiming that local prosecutors may have arbitrarily singled out their client in asking for the death penalty.

Montgomery County State's attorney Andrew Sonner has asked that James Arthur Calhoun, 27, and Curtis Wayne Monroe, 23, be put to death if they are found guilty of the widely publicized March slayings at the W. Bell and Co. catalogue discount store in White Oak.

The state's two-year old capital punishment law gives prosecutors wide discretion in requesting the penalty. Lawyers for Calhoun have argued that giving prosecutors such freedom leads to unequal application of the law across the state, thus making it unconstitutional. The U.S. Supreme Court has ruled in other state death law cases that the punishment is constitutional as long as it is not arbitrarily imposed.

Calhoun's lawyers have summoned Maryland's 26 state's attorneys to testify about how they decide when to seek the death penalty.

"The broad, unbounded prosecutorial discretion in deciding whether or not to seek the death penalty is unconstitutional," said attorney James J. Cromwell. "There is a whole panoply of procedures. As for a standard of guidelines, there is none."

Much of yesterday's testimony was closed to the press and the public on orders from Judge William M. Cave. Sonner testified that since capital punishment became effective in 1978, there have been 10 murder cases in the county where he could have sought the death penalty. He has requested that penalty in only two cases so far -- Calhoun and Monroe.

In Calhoun's case, Sonner said he decided to seek the death penalty because one of the victims was an on-duty police officer, Calhoun had a criminal record and was an escapee from Lorton prison at the time of the murder. He said the decision to seek the penalty was made only after consulting other staff attorneys.

Asked if public outcry surrounding a case ever affected his decision, Sonner said, "I do have a duty to reflect public opinion . . . They must be satisfied with how their prosecutor exercises his authority."

Sonner said he considers whether the victim is young, whether the jury is likely to sentence the defendant to death and whether there are "mitigating circumstances." He said he never considered a defendant's race and never used the death penalty threat as leverage to force a guilty plea.

Sonner revealed during the testimony that he decided on Wednesday to seek the death penalty in another, unrelated murder case -- that of Jackie Hughes, the Northwest Washington man indicted in the March 2 slaying of Richard G. Edwards, manager of Bish Thompson's seafood restaurant in Bethesda.

Sonner said he also is considering seeking the death penalty in the case of Napolean Carlton Garrett, who was indicted in June in the murder of Karen Louise Hackney and the shooting of her companion, Samuel O'Neil Hughes. Garrett is in a New Jersey jail and local prosecutors are still seeking to have him transferred here.

Since the death penalty was enacted, local prosecutors across the state have been seeking it in increasing number of cases, said Deborah Handel, chief of the criminal appeals division in the Attorney General's office. But no convict has been put to death in the state under the 1978 law, she said.