The police chief of District Heights, a small Prince George's County community that has seen little if any conflict in government over the past two decades, in what some residents charge was the direct result of the arrest of a city commissioner's son.

At a meeting last week, commission members and Mayor William. E. Hay refused to discuss why they had fired Chief Charles T. Carlson effective June 11, only saying that it was a personnel matter and that it couldn't be discussed publicly. The chief, who has been in office for eight years, holds an appointment that must be renewed annually. The reappointment has been routine up until now, and city officials said there have been no previous public disputes between the chief and the commission.

But a dozen city residents who spoke in the chief's favor at the meeting--including former mayor David H. Goldsmith--said they believe it was because of the May 11 arrest of Monroe Chew V, 23, son of commissioner Monroe Chew IV. The younger Chew was charged with possession with intent to distribute the drug PCP and was released on $6,000 bond.

Residents--including Goldsmith; Gary Powers, a Prince George's County sheriff's deputy and former city police officer; and Fire Chief Ronald Bobo--said that if the action is ever explained officially, they expect the commission to maintain that the chief was dismissed for violating a city rule that requires advance permission to moonlight. For about a year, the chief has worked as a night security guard at a construction project. The chief acknowledged Friday in an interview that he had not given notice to the commission about the outside work.

But Goldsmith contended at the commission meeting that the requirement is a technicality that is rarely enforced, and one that could be resolved without the chief's firing. They noted that the city's clerk-treasurer has an outside job as the treasurer for the town of Morningside, and that the recreation director performs regular part-time work as an official at sporting events.

His firing was "more political than anything else," Carlson said after last week's meeting.

His first official notice was May 27, Carlson said. Sixteen days earlier, two District Heights officers had arrested the younger Chew after they pulled from his car several tins of what police said they suspected was PCP.

Police clerk Elizabeth Haymans, in an interview, said she had overheard Commissioner Chew tell the chief, "You haven't heard the last of this," the next day when Carlson would not use his influence to release the son's car, which had been impounded by Prince George's County police.

Commissioner Chew, interviewed last week, said: "All I can say right now is there will be no comment about the entire episode . . . about the chief or my son."

Commissioner Edward J. Webb in a closed executive session last month nominated Carlson to continue in the $20,000-a-year job. But neither Mayor Hay nor either of the other two city commissioners seconded the motion, according to City Attorney Regis A. Johnston.

The chief has hired a lawyer, Benjamin Wolman, and plans to challenge the firing.

Residents of the middle-class community of 7,000, located just over the Southeast District line, said they were shaken by the turn of events. It is a community, they said, that was without much conflict in government during the 25-year tenure of Michael Roll, the long-term mayor who died in 1981.