James S. Sweeney, point guard, playmaker and captain of the 1978-79 Boston College basketball team and an academic all-America and nominee for a Rhodes Scholarship, said in federal court today that he knew he should have reported an alleged point-shaving scheme that season to his coach and athletic director.

He said he didn't do so because he feared for his personal safety and he doubted the ability of legal authorities to protect him.

"I was afraid the bettors would get to me first," Sweeney said.

"I was told that people in Pittsburgh and New York were interested in shaving points on Boston College basketball games," Sweeney testified in U.S. District Court in Brooklyn.

" 'You're an excellent cover. No one would suspect you,' " Sweeney said he was told by a convicted felon named Henry Hill. " 'Don't make matters difficult for us because we can make trouble for you. We expect you to cooperate. We are backed by powerful and influential people in New York.' "

For more than six hours on the witness stand Monday and today, Sweeney, captain or cocaptain of the Boston College team for three consecutive seasons, relived the trauma of that 1978-79 season as the trial of five men accused of conspiring to shave points in six Boston College games that year entered its sixth day.

Accused in the case are Richard Kuhn, 26, a former friend of Sweeney's and a reserve forward on the 1978-79 basketball team; James Burke, 50, a reputed organized-crime figure serving time for a 1974 extortion conviction; Anthony Perla, 31, of Pittsburgh and his brother Rocco, 26, a high-school classmate of Kuhn's, and Paul Mazzei, serving time on a narcotics conviction.

Sweeney, 23, testifying for the prosecution, said Kuhn, the Perla brothers, Hill and a man identified only as Pauli attempted on several occasions to enlist his cooperation in the alleged point-shaving scheme in which they stood to make thousands of dollars betting.

But although he said he agreed to cooperate, he insisted he never actually delivered on his promise. After the Boston College-Harvard game in December of 1978, he said, he accepted a $500 payment from Kuhn simply to give the illusion of cooperating with the gamblers.

Sweeney, who said the government has made no promises that he will be immune from prosecution in the case, first took the witness stand Monday following five days of testimony by, and cross-examination of, Hill, 38, a government informant.

According to Hill's testimony, the alleged point-shaving scheme originated after he was called by Mazzei, who said he had a friend in Pittsburgh, Anthony Perla, whose brother Rocco was a good friend of a player on the Boston College basketball team. The reference was to Kuhn.

They eventually worked out a plan, Hill testified, that called for Kuhn to identify games in which the point spreads were best suited for wagering coups and then to manipulate the final scores.

To ensure Kuhn's cooperation, Hill said, the player had been given cocaine on occasion and threatened with violence.

A third player on the Boston College team that year, Ernie Cobb, who led the club in scoring with a 21.3-point average, also has been implicated in the alleged point-shaving scheme and was said by prosecutor Edward A. McDonald to have been given $1,000 to see that Boston College beat Harvard by less than the point spread.

Cobb has not been indicted in the case and has denied complicity in any such scheme.

Testifying under cross-examination today, Sweeney said that before the start of each season, the players routinely met with Coach Tom Davis and Athletic Director William J. Flynn, a former FBI agent. At those meetings, they were warned against the possible tampering with game outcomes by gambling interests, he said, and were told to report any overtures immediately.

But, said Sweeney, "I didn't want to make waves. I thought I could work it out on my own, that nothing would ever come of it . . . "

It was at a meeting in a hotel room near Boston's Logan International Airport that the alleged scheme was first outlined to him, Sweeney said, and the recollection of that meeting haunted him every day throughout the basketball season.

The first game to figure in the alleged point-shaving conspiracy was a Dec. 6, 1978, game against Providence, but Boston College won that contest handily, easily covering the point spread.

A few days later, before the Boston College game against Harvard, Sweeney testified, Kuhn came to him and asked if he were interested in a point-shaving scheme for the Harvard game.

When Sweeney said he wasn't interested, Kuhn answered, "Are you crazy? These people have just lost money on our game against Providence. They are looking to win that money back against Harvard."

Boston College won that game by three points, but failed to cover the point spread, which was six, meaning that the gamblers won their wagers.