A federal judge here has told prosecutors they cannot present evidence about 4 1/2 tons out of a total of about six tons of marijuana seized in two raids on the Eastern Shore last June because federal agents entered a house and confiscated the drugs without a search warrant.

Drug agents seized 4 1/2 tons of marijuana inside a farmhouse in Chincoteague, Va. early in the morning of June 12, hours after confiscating more than a ton of marijuana at a house in Easton, Md., some 75 miles away.

According to testimony at a court hearing, one of the eight defendants in the case scheduled for trial on charges of conspiracy to distribute marijuana - who has since jumped bail and disappeared - told the drug agents who arrested him during the Eastern raid that he knew where they could find nine tons of marijuana.

The drug agents testified earlier this month that they were afraid news of the Eastern arrests would spread to Chincoteague and the marijuana would be removed if they stopped to get a search warrant.

So one agent testified, when he found the farmhouse described by the informant he broke through the locked driveway gate with his car, knocked on the front door, and announced himself as a federal officer.

When he heard "scuffling noises" inside, he said, he entered the house with his gun drawn and saw the four tons of marijuana.

Judge Edward S. Northrop said a Virginia State court was located only minutes away from the farmhouse, so if would not have been difficult to keep the house under surveillance while agents obtained the search warrant.

However, the ton or so of marijuana seized previously at Easton was outside the house being transferred from a van to a pickup truck, when agents saw it, so that remains admissible evidence, Northrop said.

Northrop's ruling was the third major setback in the case for federal prosecutors who claimed to have smashed the area's largest marijuana smuggling operation with the raids.

On Aug. 11 a federal magistrate said the prosecutors could present evidence dealing only with 132 pounds of the marijuana seized in Easton because drug agents had burned the rest, thus preventing the defendants' attorneys from examining the evidence.

Prosecutors, arguing that such burning is routine in other areas, such as along the Gulf Coast, where seizures of tons of Marijuana are common, have appealed that ruling to Northrop.