Two Washington area men, whose arrest last April launched federal and congressional investigations into possible drug use by congressmen and Capitol Hill aides, were indicted yesterday by a federal grand jury on charges of running a cocaine distribution ring.

A U.S. District Court grand jury here charged that Douglas W. Marshall, 27, of Northwest Washington, and Troy M. Todd Jr., 23, of Potomac, had conspired for nearly four years, from Sept. 1, 1978, until their arrest, to possess and distribute cocaine.

U.S. Magistrate Jean F. Dwyer immediately issued a warrant for their arrest and set bond at $1 million for each after Assistant U.S. Attorney Daniel J. Bernstein said in court that the government believes they are out of the country.

The arrest last April 19 of Marshall, Todd and a third man, Robert A. Finkel, 29, occurred after they allegedly sold eight ounces of cocaine to an undercover D.C. police officer.

Shortly after the arrest, Finkel, who allegedly worked for Todd and Marshall, began cooperating with authorities and told them that a ring supplied cocaine and marijuana to Capitol Hill and used a network of congressional aides to supply drugs to government offices and congressmen, according to law enforcement sources. The original charges against all three men were subsequently dismissed to give a grand jury time to investigate the alleged ring, these sources said.

Finkel was named as an unindicted coconspirator in yesterday's indictment along with a fourth person, Devon Dupres, a friend of Marshall's and Todd's who is now also cooperating with authorities, according to law enforcement sources.

Last July, the Justice Department and the House of Representatives launched separate investigations into the drug allegations after a controversy developed over whether prosecutors were pursuing them.

The U.S. attorney's office here, at the request of top officials in the Justice Department, then decided to break a longstanding policy of not investigating drug users and agreed to pursue the allegations of congressional drug use. A special task force of investigators from the U.S. Drug Enforcement Administration, the D.C. police and Capitol Hill police, are continuing to investigate the allegations.

The House ethics committee is also pursuing allegations of possible drug use and illicit sex on Capitol Hill under the supervision of Washington lawyer Joseph A. Califano Jr., who is serving as special counsel to the committee.

In addition to conspiracy, yesterday's 10-count indictment charges Marshall and Todd with the sale and possession of the cocaine allegedly sold to the undercover detective and with traveling interstate between Maryland and the District to further the scheme.

Marshall is a former congressional page and was briefly a Hill mail clerk, sources said. Finkel had been an elevator operator on the Hill, sources said.

Sources familiar with the investigation say Dupres was the informant referred to in recent published reports who, outfitted with a hidden transmitter, helped investigators tape a conversation last summer with Rep. Barry Goldwater Jr. (R-Calif.).

William O. Bittman, Goldwater's lawyer, said yesterday that Justice Department officials have told him within the last two weeks that the congressman "is not the target of an investigation." Bittman said department officials refused to comment on his inquiries about the recently reported taped conversation.