A federal judge yesterday limited the use U.S. prosecutors may make of key evidence in the trial of two men accused of fatally shooting a Lorton inmate last May and chastised them for the way the evidence was handled.

"Well, well, son, I tell you it's a weak chain of custody. I am really shocked and surprised," U.S. District Judge Robert R. Merhige Jr. told prosecutor Joseph Aronica in ruling on what prosecutors may tell the jury about a gun and bullets retrieved in the slaying.

Merhige said in the presence of the jury he was surprised that many people had easy access to the Fbi's evidence storage room in Alexandria. Law enforcement officials usually keep such items under tightly controlled access to prove in court it has not been tampered with.

Under Merhige's ruling, prosecutors may show the bullets to be those extracted from the body of inmate Douglas M. Boney after he was shot to death last May 23 in an apparent drug-related incident. But they may not connect the bullets to a gun linked through court testimony to the two men on trial in the case.

Defense attorneys representing the two -- Edward Ford, 32, of Alexandria, and Germain P. Stoddard, 24, of Northwest Washington -- said later they were pleased by the ruling, believing it will force prosecutors to rely more heavily on the testimony of an eyewitness to the slaying who is a confessed accomplice in the murder.

Ford and Stoddard have pleaded innocent to murder and conspiracy charges in the shooting death.

Much of the trial's second day yesterday was taken up with procedural arguments over the disputed evidence.Shortly after the prosecution rested late in the day, lawyers for Stoddard said they would present no defense witnesses.

In opening arguments Wednesday, Aronica argued the shooting at the D.C. Prison facility at Lordon in suburban Fairfax County grew out of a rivalry between Ford and the 35-year-old Boney over the sale of drugs, some of which were sold inside the prison itself.

The prosecution's star witness, John Elbert Landon, testified he saw Ford shoot Boney twice with a pistol as Stoddard stood nearby. Landon has pleaded guilty to attempted murder in the case and is serving a 10-year sentence.

Landon also testified there were five men -- not three as police earlier believed -- who burst into the minimum security facility, located 20 miles, south of Washington, at 3:15 a.m.

Several Fairfax County police officers and FBI agents testified yesterday that for the first few hours after the shooting they believed that four men might have been involved.

Several days after the incident, police officials modified their earlier statements to say definitely that only three men were among the conspirators. Landon's testimony was the first public indication that two others were involved and apparently are still at large.

Ford's defense attorneys, P. David Gavin and Thomas Rawles Jones called a dozen witnesses yesterday to chip away at Landon's testimony, given Wednesday, which remains the heart of the prosecution case.

Lorton inmate John D. Irby, a convicted heroin dealer, testified that he did not believe Ford ever had wanted to kill him. Landon had claimed during his two hours on the stand that Ford wanted to kill both Boney and Irby.

Virginia Beach businessman Steve Schatzman, who said he ran a marketing company and invested in real estate, testified he expected to see Ford in the resort city during the day on May 23, the date of the shooting. Ford had told police he was headed to Virginia Beach before his arrest, sources said.

Ford's current wife and another woman also testified they believed Ford was heading for Virginia Beach on the night of the shooting.

Ford, a solidly built man with a goatee and receding hairline, did not testify in front of the jury. However, he spent less than five minutes on the stand -- when the jury was out of the room -- to say that after his arrest he knew he did not have to talk to police without his attorney being present. Gavin previously had failed to convince Merhige that Ford's constitutional rights were violated when police talked with him before an attorney had arrived.

The jury is expected to begin considering the case after final arguments today. Each man faces life in prison if convicted of either murder or conspiracy. Merhige, whose courtroom manner is direct and forceful, expressed increasing dissatisfaction yesterday with the methods prosecutors were using, particularly in leading their own witnesses through testimony.

"We are going through so much legal mumbo-jumbo here we're not going to get justice done," the Judge told Aronica at one point. When another prosecutor, assistant U.S. Attorney Karen P. Tandy, objected to a line of reasoning Merhige was expressing, a red-faced Merhige snapped, "I don't think arguing with me would be helpful, thank you ma'am."