U.S. District Judge Oliver Gasch refused yesterday to block an FBI investigation into possible tampering with the jury that was unable to reach a verdict in the bribery-perjury trial of Rep. Daniel J. Flood (D-Pa.).

Gasch ruled that despite contentions by Flood's lawyer, Axel Kleiboemer, that the FBI probe may reflect unfairly on the ailing 75-year-old congressman, the investigation "is the proper way to proceed."

During jury deliberations earlier this month, Gasch said he received a note from one juror saying that another juror, identified later as William Cash, had information relating to Flood that did not come from the evidence. The information was that a key government witness, Flood's former administrative aide, Stephen B. Elko, along with others, had allegedly stolen $176,000 from Flood and that a $47,000 check was involved.

Gasch said that when he questioned the juror about the figures, Cash claimed that they were "the product solely of his imagination." Despite further deliberations, the jury said it could not reach a verdict and a mistrial resulted.

But Gasch, in a four-page ruling, said that when he learned later that Elko had given a similar story to FBI agents a year ago, "this highly unusual circumstance raised in the court's mind the clear possibility that there may have been extraneous contacts with the jury at some point.

"The government is entitled to carry on its investigation, separate and apart from any inquiry the court has made or might wish to make, with some confidentiality, especially since the defendant in this case may be considered as one subject of the investigation," the judge said.

At the same time, Gasch rejected a defense bid for an outright acquittal of Flood, saying that discrepancies in the testimony from prosecution witnesses "do no dispel the possibility of memory lapses concerning events many years ago."

The government has tentatively set the retrial of Flood and Gasch for June.