A former federal prosecutor told legislators today that a key witness in the investigation that led to resignation of Vice President Spiro T. Agnew told him he would have "taken his medicine - gone to jail" instead of cooperating if he had known what an ordeal was before him.

Former U.S. Attorney George Beall was urging the Maryland Senate Constitutional and Public Law Committee to go easy on legislating against "finks, rats and snitches' who blow the whistle on corrupt public officials because many times they get a worse deal than those they have bribed.

The committee is considering a bill that would disqualify persons who have been connected with bribing public officials from seeking contracts with the state.

Beall, whose staff brought charges against Agnew, Gov. Marvin Mandel and former county executives Dale Anderson and Joseph Alton, said that while businessmen who bribe elected officials and then testify against them "are not praiseworthy (and) they shouldn't be rewarded," it may not be "in the public interest" automatically to disqualify them from doing further business with the state.

Not only are they unlikely to bribe again, Beall said, but they probably have lost their jobs, their professional licenses in the instances of engineers and architects and "been drummed out of their lodge." Also, some will have gone to prison, Beall said.

"Because we are taught not to be snitches and rats, there is very little inducement for legitimate law enforcement officials to get cooperation" from persons who have information critical to criminal investigations, Beall said.

So Beall said, prosecutors cajole prospective "finks" with suggestions that their testimony is available from other sources so they had better "get on the boat" before it sails without them, leaving them with no bargaining power to protect them from their pending indictments.

During the Agnew probe, he recalled, one key witness was about to cave in to that pressure, until his lawyer advised him that "with the baggage you've got, the boat will come back and get you."

It was that same witness who Beall said told him on a Baltimore street corner nine months ago that he was sorry he had cooperated because he had suffered so much since then.

Although Beall did not identify him, reporters Richard Cohen and Jules Witcover, in the book "A Heartbeat Away," attributed the first part of the story to engineer Lester Matz.

Beall said witnesses end up cooperating out of "enlightened self-interest. It's not a very nice business - it's a dirty business," Beall said.

The former prosecutor, who now is in private practice in Baltimore and sometimes defends criminal suspects, said allowing cooperating witnesses to bid on state jobs is a small concession, a chance to rehabilitate.