Raymond S. Pyles, 60, who retired in 1970 as assistant chief of the Washington police department, died of cancer Monday at his home in Rose Haven, Md.

He had held a number of key positionss during his 28 years on the police force.

In 1968, as a deputy chief, Mr. Pyles headed the department's Special Operations Division, which included the Civil Disturbance Unit. The Division played a major role during theApril riots that broke out here after the assassination of civil rights leader Martin Luther King Jr.

While a number of areas of the city, including the 14th and Seventh Street corridors in Northwest and the H Street corridor in Northeast, were heavily damaged, most of the rest of the city was spared fire and extensive looting before military assistance arrived.

Later in 1968, the Poor People's Campaign marchers settled into Resurrection City on the Mall. Chief Pyles played a key role in keeping the scene peaceful.

Several years earlier, in 1965, within the rank of inspector, he had commanded the newly-established Tactical Force, set up to combat street crime in Washington. Made up of uniformed and plainclothes officers drawn from the city's police precincts and deployed to trouble spots, it was credited with bringing about a sharp reduction incrime.

He and a civilian assistant were responsible for hiring 1,500 rookie policemen within a six-month period in 1970 to bring the police force up to a presidentially-ordered goal of 5,100 men. Chief Pyles also was credited with reducing sick leave abuses and unwarranted disability retirements in the department.

He was born in the Anacostia section of Washington and attended Eastern High School. He joined the police force in 1942 and was assigned to the 11th precinct, whose station house was within a block of his birthplace.

He entered the Army in 1944 and was attached to the 87th Mountain Infantry Regiment of the 10th Mountain Division, seeing combat in Italy.

After the war, Mr. Pyles returned to the police department. In addition to the 11th precinct, he served in the 14th and 1st precincts and in the 3rd, which he commanded in the early 1960s. He also was in charge of the entire uniformed force at one time.

In 1974, the Federal Aviation Administration named Mr. Pyles chief of police at National Airport. He held that job until 1976.

Mr. Pyles was a member of the Association of Retired Policemen and belonged to the Anacostia Lodge of the Masons. In recent years he had worked with the Boy Scout cub pack of handicapped children.

A resident of Clinton, Md., for many years, he had moved to Rose Haven four years ago.

He is survived by his wife, Dorothy, of Rose Haven; two daughters, Nancy C. Ruano, of Houston, and Susan R. King, of Rose Haven; a son, Timothy, of Dunkirk, Md.; his mother, Lily V. Pyles, of Hillcrest Heights; a brother, George R., of Montross, Va.; two sisters, Dorothy E. Langford, of Colonial Beach, Va., and Maxine Martin, of Dallas, and two grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.