District Heights' mayor and City Commission have agreed to extend the employment of the city's fired police chief for 60 days.

Some residents of the city are challenging the firing, which they contend was the result of the arrest last month of a commissioner's son on drug charges.

Without explanation, the commission voted May 24 to fire Chief Charles T. Carlson Jr. from the job he had held for eight years. The three-member commission and the mayor agreed to the extension Wednesday after negotiations between Benjamin Wolman, the chief's attorney, and City Attorney Regis A. Johnston.

District Heights residents said they want city officials to make that 60-day period probationary, to render a public evaluation of Carlson's performance, and to disclose their reasons should they then decide to dismiss the chief.

Carlson's supporters said he had stabilized the six-member police force that under previous administrations suffered from attrition and morale problems.

The chief also has worked another part-time job, an apparent violation of a city law that requires the commission's approval. Residents called that an "excuse" to fire the chief because other city employes have not been fired for working elsewhere without the commission's consent.

The new mayor, William E. Hay, disclosed no reason in a letter Carlson received May 27 firing him effective June 11. Residents demanding to know why Carlson was fired jammed the commission's June 3 meeting. Hay said the firing was a personnel matter that could not be discussed.