Intelsat's former chief executive, Richard R. Colino, was sentenced yesterday to six years in prison and was ordered to pay $865,000 for his part in illegally siphoning $5.4 million from the global communications agency.

Colino had pleaded guilty to criminal fraud and conspiracy charges in U.S. District Court last July. Two of his business associates pleaded guilty at that time to conspiracy to transport money taken by fraud. The charges had been brought by U.S. Attorney Joseph E. diGenova.

"I don't have any excuses," said Colino, before his sentencing by U.S. District Judge Gerhard A. Gesell yesterday. "I think that what has happened is in a real sense an aberration in a lifetime of behavior." Colino worked in the field of telecommunications for more than 20 years, culminating in his leadership of the agency that handles most of world's international communications through its global satellite system.

In his sentencing, Judge Gesell called Colino's offense graver than that of his business associates because of his position as the head of Intelsat. "Your offense is a much more serious matter, quite apart from the money, because it's such a clear breach of public trust."

The judge put the total amount of funds siphoned from Intelsat at slightly more than $5.4 million, with more than $600,000 associated with fraudulent telecommunications consulting contracts.

The judge yesterday also sentenced Washington real estate broker Manuel G. Serra to three years in prison and fined him $100,000. Serra, who received about $390,000 in kickbacks, has agreed to return $100,000 to Intelsat. Charles G. Gerrell, an Arkansas mortgage broker, was sentenced to two years in prison and was not fined. The three have cooperated in the investigation, authorities said.

The U.S. Attorney's Office has documented four transactions between April 1984 and December 1986 in which Colino and his associates fraudulently obtained $4.8 million in funds from Intelsat through bid rigging and kickbacks that went to Serra, Gerrell, the William P. Lipscomb Construction Co. Inc. of Arlington and other associates. The schemes involved rigging the bidding of construction contracts to build an addition to Intelsat headquarters at the corner of Van Ness Street and Connecticut Avenue, charges for unnecessary corrections to the original building, and the creation of false fees and expenses.

In imposing his sentence on Colino, the judge questioned the whereabouts of $3.5 million deposited in two Swiss bank accounts shared by Colino and his former deputy, Jose L. Alegrett. Alegrett was fired along with Colino last December when auditors discovered an unauthorized payment of $1.35 million to Gerrell and his former wife, Dana. Alegrett is a major part of the investigation but is believed to be in Venezuela.

"The accounts in Switzerland ... received $3.5 million in total funds," said Judge Gesell. "Up to date, we have only Colino's information that $860,000 was received {by him}, and we have no suggestion of where that money went otherwise." Colino's lawyer, Nathan Lewin, said Colino had traced $860,000 of the funds in his possession and that, based on a polygraph test that suggested Colino was telling the truth, he may have received up to, but no more than, a total of $1.1 million out of the Swiss bank accounts.

After the sentencing, Intelsat lawyer Ray Banoun disputed Colino's claims about the money he received. Colino received "at least half of the $3.5 million" in the Swiss accounts, said Banoun.

Before the sentencing, Intelsat had recovered about $1.5 million, $1 million of it from Alegrett, Banoun said.

Attorneys for Colino and Intelsat said they had been negotiating earlier in the week to resolve a $11.5 million civil suit brought by Intelsat against the former director general.

Banoun said Colino offered on Monday to pay back $1 million to Intelsat on the conditions that Intelsat drop its civil suit, that no claims be made on his wife's assets and that Intelsat inform the court that it was satisfied with the restitution.

"We turned it down because Intelsat knows that he can afford to pay more," Banoun said. Colino has disclosed more than $1.5 million in assets in a separate bankruptcy proceeding and has taken the Fifth Amendment in response to questions about where he got money to make certain purchases, said Banoun.

Colino sold his house for nearly $1 million and a Florida condominium for about $170,000, despite Judge Gesell's order that his lawyer notify the U.S. government of any transaction greater than $10,000, said Banoun. An official in the U.S. Attorney's Office denied the U.S. Attorney had signed off on any sale.

Banoun said the bankruptcy judge also had not approved any sale and had enjoined Colino from spending any amount more than $1,000 of his assets or assets owned jointly with his wife.

However, Colino's lawyer Lewin said yesterday in court that approval had been obtained "from the U.S." for the sale of certain assets and that Colino's house "has nothing at all to do with the matter before the court today."

The U.S. Attorney's Office said it is still investigating whether others are implicated in the siphoning of Intelsat funds