Last August, the month before he went on trial on political corruption charges, Maryland Gov. Marvin Mandel sat in a Baltimore studio preparing a 30-second public service message on crime prevention that's now appearing on Washington-area television and radio stations.

"I want to talk to the burglars, muggers and rapists in the audience," Mandel said, looking straight into the camera. "With the help of Maryland citizens your job is about to become a lot tougher."

To the "law abiding citizens" in the audiecne the governor added, "The criminal is no genius. He can be discouraged."

The Mandel television spot is the introduction to a statewide crime prevention awareness campaign financed by a $90,000 federal grant from the Law Enforcement Assistant Administration, according to Gary Bassford, public affairs director for the governor's commission on law enforcement.

"We thought it would help us get the attention of the media if we could lend the prestige of the governor's office to the campaign," Bassford said in explaining Mandel's participation. "He agreed to help."

The Mandel tape was mailed to 12 television and 38 radio stations in Washington and throughout Maryland two weeks ago. It will be followed, starting Feb. 1, by month-long spots on preventing street assaults, rape, burglary and citizen apathy, Bassford said.

Between the taping of the crime prevention message last August and the first airings earlier this month, the governor spent much of his time in a Baltimore courtroom, hearing a barrage of charges that he had accepted thousands of dollars in gifts and cash from friends in return for his efforts to aid a state-regulated racetrack his friends secretly owned.

A mistrall was declared Dec. 7 because of publicity about alleged jury tampering attempts.A new trial is scheduled to begin April 13.

Bassford said there was no connection between the trial dates and the timing of the public service campaign. "I hope we're all able to make the distinction between all that's gone on there (the criminal charges against Mandel) and the beginning of a worthwhile campaign to make the citizens of Maryland aware of how they can make themselves less of a target for criminals," he said. "They're different issues and I'd like to keep them separate."

Bassford noted that the states of Minnesota, Georgia, Florida and Ohio also have conducted LEAA-financed publicity campaigns on crime prevention, including particiapation by their governors.

Mandel held a reception for about 40 radio and television executives at the governor's mansion on Jan. 6 to persuade the station officials to run the free public service announcements prominently, the campaign's press spokesman added. The theme of thcampaign is "Make crime more trouble than it's worth."