A salesman for the trouble-plagued Research Homes company was indicted yesterday in U.S. District Court in Alexandria on four counts of security law violations.

The grand jury indictments follow by less than a week the sentencing in the same court of James Dyer, the former chairman of the board of now-bankrupt company. Two other individuals have entered pleas in connection with the case.

Yesterday L. Blaine Liljenquist, of McLean, Va., was indicted on one count of securities fraud, one count of conspiracy to violate the federal securities registration laws, and two counts of selling and delivering unregistered securities. The alleged acts occurred between 1971 and 1976.

Liljenquist faces a total of 20 years in prison and a $40,000 fine if convicted on all counts. Liljenquist could not be reached yesterday for comment.

According to an announcement bu U.S. Attorney William B. Cummings, Liljenquist was employed from 1971 to 1976 as a salesman in the Virginia office of Research Homes, the controversial company which has been under investigation by federal authorities for a nearly a year.

During that time, Liljenquist and unnamed others conspired to sell unregistered securities through various means in order to disguise their account numbers and value from attorneys, stockholders and Securities and Exchange Commission officecials, Cummings said.

Liljenquist allegedly sold unregistered common stock as part of "a scheme which resulted in the sale of more stock than Liljenquist owned or possessed," according to Cummings.

Last Friday James Dye received six months in prison after his conviction on similar charges.