A microphone worn by Montgomery County police officer Kyle Olinger when he was shot in Silver Spring last summer was misplaced in a police evidence room and lost for more than a year, police said in court yesterday.

The microphone, which has a bullet hole through it, surfaced Wednesday, two days into the trial of Terrence Green, 18, who is charged in the shooting. Green's attorney called the microphone "central" to the defense's case and asked for a mistrial, which Montgomery Circuit Court Judge S. Michael Pincus denied.

A police detective testified yesterday that the microphone -- a type worn on officers' chests and attached to a radio on their belts -- was inadvertently left in a box and not properly catalogued with other evidence from the shooting.

In May, a property clerk sent an e-mail to the head of the department's homicide and sex section alerting him that the radio had been found but that information was not conveyed to those involved with the case. But the radio and microphone remained missing until Wednesday, when a detective decided to check once more.

Green's attorneys yesterday urged Pincus to declare a mistrial, saying the mistake prevented them from incorporating the evidence into their defense.

"We have selected experts in this case . . . who have rendered opinions solely on the basis of what was available to be reviewed," defense attorney Rene Sandler said. "We have other individuals that were consulted with but made the strategic decision not to call as witnesses based on the state of evidence as we understood it to be."

Though Pincus denied a mistrial, he restricted testimony about the microphone.

Prosecutors and Green's attorneys agreed that the microphone was inadvertently misplaced.

"Nobody is saying that this is an intentional violation," Montgomery County State's Attorney Douglas F. Gansler said in court. "It was inadvertent."

Capt. John Fitzgerald, a police spokesman, said, "If we made mistakes, we'll try to find out how that happened and make sure it doesn't happen again."

The microphone played a central role in spurring the investigation into Olinger's shooting early on Aug. 13, 2003, but Gansler said yesterday in court that it is of minimal importance to the state's case.

The state alleges that Green intentionally fired a .32-caliber handgun into Olinger's neck during a routine traffic stop. The defense has signaled that it will not so much dispute that Green was the triggerman as argue that he did not intend to shoot Olinger. Olinger, 38, survived the shooting. His legs remain paralyzed.

Green is charged with first-degree attempted murder, first-degree assault and use of a firearm in a crime of violence.

A cabdriver who saw Olinger on the ground moments after the shooting used the microphone to call out, "Officer down," on the police radio.

The microphone has a small hole in the front and a slightly larger hole in the back, indicating that the bullet passed through the radio before entering Olinger's neck, Gansler said.

"Obviously, the microphone could still function because [the cabdriver] used it to make a call out," Gansler said.

Police descended on the scene shortly after the cabdriver's call and within hours arrested Green, along with Fadi Kadamani, 21, who drove the car in which Green rode.

Officer Kyle Olinger was shot in the neck. His legs remain paralyzed.