Six-month probe finds insufficient evidence to prosecute Donovan

US Labor Secretary Raymond J. Donovan may still have his problems with organized labor and some White House officials. But a six-month investigation finds ''insufficient credible evidence'' to support allegations of criminal wrongdoing.

For months Mr. Donovan has been fighting charges that he committed perjury, had ties to organized crime, and attended a luncheon where a bribe was paid to a union official.

Now, however, Special Prosecutor Leon Silverman, who was appointed to head the investigation, ''concludes that no prosecution of the secretary, on any of the allegations investigated, is warranted or could successfully be maintained, '' according to the summary of a massive 1,025-page report.

Mr. Silverman also stressed that the federal grand jury convened to hear charges of criminal wrongdoing against Secretary Donovan chose not to prosecute.

The report said that at first, federal investigators focused on the primary allegation that Mr. Donovan, former executive vice-president of the Schiavone Construction Company of Secaucus, N.J., was present at a luncheon in 1977 at which an illegal $2,000 payoff was made to a union leader.

The man who made this allegation was Mario Montuoro, a former official of Local 29 of the International Laborers Union in New York City. But the report said that his statements themselves ''diverged widely.'' Furthermore, the report said federal prosecutors failed to determine that the luncheon even took place: ''Montuoro's specifications by month or week were inconsistent.''

The allegation generating perhaps the most publicity in recent months was that Mr. Donovan had ties to organized crime figures. Here again, Mr. Silverman, a prominent New York attorney, said he ''failed to uncover credible evidence that Secretary Donovan . . . had such associations.''

The special prosecutor reiterated at a news conference that allegations that Mr. Donovan in 1978 made an illegal payoff to a union leader who was associated with The Trib, a short-lived New York City newspaper, was unfounded. Reuters also reports:

In connection with allegations that Mr. Schiavone violated federal laws by entertaining union officials at company expense, the report says that union officials were in fact entertained by the company. However, Mr. Silverman stated that ''it is highly dubious that any crime was committed; no successful prosecution could, moreover, likely be sustained.''

The report did say evidence was found corroborating an allegation that the Schiavone construction company, one of the largest builders in the northeastern United States, had hired ''no-show'' employees on a New York City project. The report said there was evidence that perjury was committed before the special grand jury on this point, but that perjury was not committed by Mr. Donovan.