Prosecutors acted improperly when they secretly obtained tapes of Manuel Noriega's jailhouse phone calls, but their actions do not warrant dismissal of the drug charges against him, a federal judge ruled.

U.S. District Judge William Hoeveler ruled Monday that the prosecutors' actions did no real damage to the former dictator's defense.Prosecutors secretly subpoenaed the tapes from the Metropolitan Correctional Center, where Noriega has been held since shortly after his surrender in January 1990. Inmate calls are automatically taped at the jail.

The U.S. attorney's office hid the subpoenas from Noriega's defense team and had no legal basis for issuing them, the judge wrote.

The result was "a broad dragnet aimed at bringing in anything and everything contained in the recordings," the judge said. "This is precisely the kind of unwarranted expedition which (the judicial code) does not permit."

The written opinion elaborated on a Hoeveler's decision from the bench in January not to dismiss the case.

A member of the Noriega defense team, which had sought dismissal of the case, said he was pleased with the ruling on the subpoena issue.

Secretly subpoenaing the tapes "was a fairly gross act of overreaching by the prosecution team engaged in a fishing expedition," said defense attorney Jon May.

"This is also an important decision because it is the first condemnation of a practice that has been widespread among prosecutors around the country."

The U.S. attorney's office did not dispute the judge's finding that prosecutors played fast and loose with the Federal Rules of Criminal Procedure.

"We regret the inconvenience to the court," said spokeswoman Diane Cossin. "We will pay close attention to discovery and inspection rules according to the federal rules of criminal procedure."

The subpoenas came to light when CNN broadcast excerpts from the tapes in November.

Prosecutors acknowledged subpoenaing the tapes as if they were needed as evidence in a court hearing, even though no such hearing was scheduled. That type of subpoena does not require notification to the defense.

Noriega goes on trial July 22 on charges he took payoffs to protect the Colombian cocaine trade.