Prince George's County Executive Lawrence J. Hogan yesterday rejected a request by the county Human Relations Commission that a new charge be brought against county police officer Lester Bethel, who was fined $100 by a police trial board after he shot and killed a burglary suspect last year.

The Human Relations Commission asked Hogan to reopen Bethel's case in April after completing a review of the highly publicized Jan. 21, 1978, shooting and the trial board's findings.

Bethel, who shot Abraham Dickens IV as he was climbing unarmed through the window of a Seat Pleasant restaurant was found guilty by the trial board of unauthorized use of a shotgun, a technical violation, but was cleared of other charges.

Hogan told the Human Relations Commission in a letter released yesterday that he would not reopen the case because of state law that prevents him from ordering a new hearing for an officer who has been cleared.

Bethel's supporters applauded Hogan's action and criticized the Human Relations Commission for seeking to reopen the case. But leaders of the commission's law enforcement practices panel, which sought a new charge that Bethel used "excessive force" when he fired at Dickens, said that Hogan "had not faced the issues" in the case.

A leader of the country chapter of the American Civil Liberties Union, Fred R. Joseph, said the ACLU would consider using Bethel's case to test the state law that Hogan cited. The state law supersedes a county law that would have required Hogan to order a new trial board for Bethel after the Human Relations Commision requested it.

The Human Relations Commission sought the new charge agaisnt Bethel because of what it said was the trial board's failure to consider Bethel's use of magnum shotgun ammunition that was not issued by the police department. The commission also cited what it said were discrepancies in testimony at Bethel's first hearing.

Acting Police Chief Joseph Vasco contended in a memo to Hogan, however, that the commission's findings were "inaccurate." Citing the state law, Vasco recommended that Hogan take no action on Bethel's case.

The shooting incident occurred shortly after another Prince George's officer, Peter Morgan, shot and killed a suspect outside the Seat Pleasant police station, and the two cases led to protests against the police, highly publicized investigations, and some changes in department rules.

"The Human Relations Commission was looking for more publicity," Laney Hester, the county's Fraternal Order of Police president, charged. "They are like a batter that swings after the ball has already gone by."