A man convicted of swindling thousands of investors out of millions of dollars in a phony diamond scheme will serve his entire six-year prison term without parole, the Utah Board of Pardons said Friday.

Jon C. Vasilacopulos, who has been imprisoned since 1985, will go free Aug. 9, 1991.Parole board members said the 31-year-old swindler deserved all the punishment his sentence allowed.

"It's outrageous activity that needs to be punished," board member Paul Boyden said.

But board members also expressed regret that their decision will put Vasilacopulos beyond their power to force him to pay back some 3,000 investors he bilked of more than $12 million.

If the board had paroled him, Vasilacopulos could have been made to repay some portion of that sum.

However, board Chairwoman Victoria Palacios said victims may bring civil suits against Vasilacopulos.

"Board restitution is not the only way to compensate them," she said. "And, frankly, Mr. Vasilacopulos, you owe them."

Board member Gary Webster said many elderly people were victimized by the scam, in which Vasilacopulos sold the same diamonds over and over again to different buyers. Many invested their life savings in the bogus venture, Webster said.

As a result of a plea bargain, Vasilacopulos was originally sentenced to three counts of theft by deception. One count was a second-degree felony punishable by one to 15 years in prison; the other two were third-degree felonies with zero-to-five-year terms. The three counts were to be served consecutively.

However, the Utah Court of Appeals vacated the guilty pleas last year after determining that Vasilacopulos was not informed that he could receive consecutive sentences for the each of the counts.

Following the reversal, Vasilacopulos pleaded guilty to two consecutive zero-to-three-year terms of security fraud.

Before the reversal, Vasilacopulos was to have been paroled after serving nine years in prison.

While in prison, Vasilacopulos has had an "outstanding record," board members said. He is working on a college degree and has completed a correspondence course in law. He hopes to attend the University of Utah upon release from prison and hopes to someday work as a paralegal.