Jerry Lee Beatty, one of two men convicted of murdering Frostburg (Md.) State College student Stephanie Ann Roper in 1982, went on trial for a second time yesterday on rape and other charges that were pursued by Prince George's County prosecutors in an attempt to lengthen the minimum time he must serve in prison.

Beatty is accused in Prince George's Circuit Court of raping Roper in Prince George's before she was killed in St. Mary's County.

He plans to plead not guilty by reason of insanity, his attorney said yesterday.

Prince George's prosecutor Michael Whalen said that if convicted on the charges, which also include sexual assault, conspiracy and weapons charges, Beatty could face "between three and four life sentences" in addition to the life sentence he has already received for the murder. He would have to serve a minimum of about 12 years for each sentence before being eligible for parole consideration.

In April 1982, Beatty, then 17, and Jack Ronald Jones, 26, kidnaped the 22-year-old Roper after stopping on a deserted country road in southern Prince George's to help with her disabled car. The honors art student was raped, beaten, shot and set afire.

Later that year, both men were convicted of murder and sentenced to concurrent life sentences.

Under state law, prisoners serving life sentences can become eligible for parole consideration in a minimum of 12 years, but authorization for their release would have to come from the governor.

Prince George's State's Attorney Arthur A. Marshall Jr. said yesterday that he wanted to pursue the additional charges because he did not consider the minimum time the men currently have to serve "appropriate punishment for the kind of crime they committed."

Roper's parents and their supporters felt that the murder sentences for the two slayers were far too lenient.

Their outrage sparked the formation of an influential victims' rights organization called the Stephanie Roper Committee, which has successfully lobbied the Maryland legislature for stricter sentencing for violent crimes.

After Beatty and Jones were convicted in 1982, Marshall pressed ahead on the additional charges, and the men were indicted by a grand jury in Prince George's. Defense attorneys argued that trying the men again was double jeopardy.

In 1983 Circuit Court Judge Jacob S. Levin, who is presiding over the current case, ruled that the men could be tried on the additional charges, a decision that was upheld by the Maryland Court of Special Appeals.

Jones is scheduled to be tried later this year.