After an investigation lasting 10 months, the Senate Ethics Committee said yesterday that the transgressions of former senator Edward W. Brooke (R-Mass.) were not serious enough to warrant any punishment.

The committee said it could find no evidence of any wrongdoing on Brooke's part except for a sworn mis-statement regarding his personal finances that Brooke previously admitted was false.

Allegations of improper behavior on Brooke's part contributed substantially to his defeat in November by Paul Tsongas (D-Mass.). Brooke was the only black member of the Senate.

"I'm not bitter," Brooke said repeatedly in a telephone interview yesterday, adding that he regarded the Ethics Committee's report as a vindication.

"It all started mushrooming," Brooke said of the allegations against him that appeared persistently last year, mostly in newspaper accounts. "I got caught up in it, and I didn't know where it was coming from."

Later in the interview, Brooke acknowledged that, in fact, he did know where it all started -- in a messy divorce proceeding with his long-estranged wife, Remigia. During a bitter battle over the division of their assets, Brooke swore in a deposition taken by his wife's lawyer that he owed a man $49,000 when, in fact, he owed only $2,000.

That $47,000 discrepancy, the Ethics Committee said yesterday, amounts to "the giving of false testimony under oath by a United States senator," and is "improper conduct which reflects unfavorably on the United States Senate."

But, the committee found, this was not "sufficiently serious to justify the severe disciplinary actions specified" in Senate rules -- censure, expulsion, or a recommendation that a senator be stripped of seniority or positions of responsibility.

Since Brooke is no longer a senator, however, the committee's role in his case is moot. Because he is not a senator, "no further investigation pursuant to the committee's rules of procedure is required," the panel said.

The committee said it had found "credible evidence which provides cause to conclude that violations within the jurisdiction of the committee have occurred."

"I can't condone a misstatement under oath," Brooke said yesterday. But he noted that it had taken place "outside the courtroom," and added that "if you're ever in a divorce, you'll discover that they're more interested in your assets than your liabilities."

Brooke's defeat last fall was a source of sadness and discomfort to friends and admirers in the Senate.One of them noted yesterday that the liberal Republican had been less effective in the last four years of his Senate career than he had been earlier, but that he remained a tough fighter on issues that mattered most to him.

For example, he was the leader of successful efforts in the Senate to fight off efforts by the House to ban any federal spending at all on abortions for poor women.

Black leaders say privately that Brooke was a quiet but effective operator on behalf of issues helpful to minorities, often using his Washington apartment for unpublicized but important strategic planning sessions.

The Ethics Committee report said the committee could not pass judgment on some of the complicated financial dealings it considered for want of sufficient information. One of these was a payment of $27,500 that Brooke said was a loan, but which, the committee said, might have been a return on an earlier investment. Whatever this was, Brooke failed to report it properly, the committee said.

The committee cleared him of charges that he falsely claimed his daughters as dependents on tax returns, and that he was aware of improper receipt of Medicaid benefits by his late mother-in-law.

The committee noted that Brooke's records and financial reports were often imcomplete, but said most of them were "due to the careless fashion in which the reports were prepared." The committee did not explain its use of the word "most."

The report did not address the role of its former special counsel, Richard J. Wertheimer, who resigned dramatically last Oct. 13 -- three weeks before election day -- and charged that Brooke's lawyers had withheld and altered documents important to the inquiry.

Brooke demanded a hearing on this accusation before the election. This was held, and Wertheimer used the occasion to release a 54-page statement detailing charges of withholding and altering documents. The committee on Oct. 25 cleared Brooke personally of any wrongdoing in this regard.

"That Wertheimer thing really was the nail in the coffin," Brooke said yesterday, complaining again about the timing and nature of the incident.