ROCKVILLE, Md. – Convicted sniper John Allen Muhammad agreed yesterday to let three standby attorneys assist him during his upcoming trial in six of the 2002 Washington-area sniper shootings.

Muhammad fired his court-appointed attorneys and is representing himself at the trial, scheduled to begin May 1.

The standby attorneys will provide legal advice if he requests it during trial. If Muhammad can’t represent himself for some reason, the team would become his lawyers.

One of the attorneys, J. Wyndal Gordon, said after yesterday’s hearing that Muhammad had formed coherent arguments despite his lack of legal training and questions about his mental state.

“I was impressed,” Mr. Gordon said. “He definitely is not intimidated by the system.”

Muhammad and accomplice Lee Boyd Malvo, then a teenager, were accused of killing 10 people and wounding three during a three-week shooting spree in October 2002. They were linked to several more shootings in other states. Muhammad was sentenced to death in Virginia at an early trial. Prosecutors said the upcoming Maryland trial is insurance if the Virginia verdict is overturned.

Yesterday, Montgomery County Circuit Judge James Ryan also agreed to allow 28 subpoenas from a list of 178 people Muhammad wants to call in his defense. He said Muhammad would have to provide more information about the others before approving them.

Assistant State’s Attorney Vivek Chopra accused Muhammad of employing stall tactics to stretch out the case.

“The defense is trying to grind this proceeding today and this trial to a halt,” Mr. Chopra said.

Muhammad also submitted his proposed list of questions for potential jurors. Some involved legal beliefs. One asked whether jurors believed students should wear uniforms. He also hoped to present jurors with a list of 76 words, such as “hearsay” and “brainwash,” to measure their reactions.