WASHINGTON (AP) _ The Senate has returned to the White House the nomination of Dexter Lehtinen to be the U.S. attorney in the Justice Department office prosecuting deposed Panamanian dictator Manuel Noriega.

The action is tantamount to rejecting the nomination without a vote. This blow to Lehtinen's controversial nomination occured last week before Congress recessed for its August vacation.

It was the second rebuff by the Senate to Lehtinen. The Senate adjourned in 1990 without action Bush's original nomination by the Judiciary Committee, which had been awaiting results of a departmental investigation of him. Bush renominated Lehtinen again this year.

White House spokeswoman Judy Smith declined to comment Thursday on the Senate's action.

President Bush could send up Lehtinen's name for a third time, but the return of the nomination carries the implicit message that senators don't want him to do so.

Lehtinen, a flamboyant prosecutor who has been interim U.S. attorney in Miami since 1988, was harshly criticized this year by the Justice Department for publicly criticizing a former member of his staff through his press spokeswoman.

The Justice Department shared the results of its internal investigation with the Senate Judiciary Committee, according to a government source who spoke on condition of anonymity.

There was no immediate comment from Lehtinen's spokeswoman, Diane Cossin.

Lehtinen, known for his hot temper, once brandished a plastic AK-47 rifle during a staff meeting while delivering a pep talk on the war on drugs.

Attorney General Dick Thornburgh eased Lehtinen off the Noriega prosecution team when top Justice Department officials became concerned that Lehtinen's volatile temper and relative inexperience as a trial lawyer could hurt their case.

Noriega is scheduled to go to trial next month in Miami on drug trafficking conspiracy and bribery charges.

Lehtinen is married to Rep. Ileana Ros-Lehtinen, R-Fla., a prominent Cuban- American politician he met when they both served in the Florida legislature.

Lehtinen's fabled temper spawned news stories in Miami that his management style had driven five veteran prosecutors to leave the office in 1990.

Cossin was quoted by The Miami Herald as saying the fact the five ''stayed while Dexter has been here indicates some sort of happiness with the office.''

David DeMaio, one of the departing prosecutors, disputed her statement, and Cossin then wrote the newspaper that Lehtinen had welcomed DeMaio's resignation, adding that DeMaio was almost fired once for ''egregious misconduct.''

The Herald later obtained DeMaio's personnel file, which didn't support Cossin's statements about him

The Justice Department's Office Of Professional Responsibility, which investigated the incident, harshly criticized Lehtinen and Cossin for the letter.

Despite this criticism, President Bush resubmitted Lehtinen's nomination to the Senate.