Nine persons were arrested Saturday on drug charges stemming from a 2 1/2 month investigation of drug trafficing in far Southeast Washington and on the fringes of Capitol Hill.

Seven of the nine were arrested after an undercover officer allegedly made 60 buys, mostly of heroin, from them during the investigation, according to narcotics detective Alan Penburg. More arrests are expected, he said.

The investigation, spearheaded by Sgt. Raymon Gonzales, concentrated on drug activity around Talbert Street and Martin Luther King Avenue in Southeast and 15th Street and Independence Avenue east of the Capitol, he said.

The undercover officer purchased bags of herion for $25 and $50, Penburg said.

Arrested and charged with distribution of heroin were Ralph Magruder, 32, of 1204 Talbert St. SE; William Alston, 32, of 1523 17th St. SE; Eugene Davis, 20, of 1227 Talbert St. SE; Andre Taylor, 19, of 1634 Independence Ave. SE; Keith Robinson, 23, of 2104 Savannah Terrace SE; John H. Mathis, 23, of 1147 Oates St. NE, and John E. Burroughs, 42, of 5405 21st Ave., Hyattsville.

Stephen S. Young, 36, of 183 Elmira St. SW, was charged with possession of marijuana and heroin and Robert E. Williams, 60, of 602 Tennessee Ave. NW was charged with distribution of Preludin.