A well-known Upper Marlboro lawyer was disbarred yesterday after defending a bail bondsman on drunk driving charges while knowing the man was using a false name to hide his driving record.

The lawyer, Fred Peter Heyser, 42, and the bail bondsman, Paul E. Burch Jr., 48, have both pleaded guilty in Howard County Circuit Court to charges of obstructing justice and conspiracy in the 1984 drunk driving trial. Heyser received a suspended sentence April 8, and Burch is scheduled to be sentenced today.

Lawyers for the state and Howard County prosecutors said Burch had obtained a driver's license in his 12-year-old son's name when his own license was revoked after several drunk driving convictions. He was later arrested by Howard County police on a charge of driving while intoxicated and a District Court judge, believing Burch a first-time offender, put him on probation without entering a conviction in his record.

Heyser, who knew Burch, upheld the fiction that Burch was someone else and, except for a minor slip-up during the District Court trial that no one noticed at the time, referred to him by his son's name.

Heyser could not be reached for comment.