Intelsat's former chief executive, Richard R. Colino, and two business associates pleaded guilty in U.S. District Court yesterday to criminal fraud and conspiracy charges stemming from $4.8 million that was siphoned from the international communications satellite agency during construction of its headquarters in Washington, D.C.

Colino, who came to court pale and with his right arm in a sling because of a shoulder operation, was charged by U.S. Attorney Joseph E. DiGenova with fraudulent interstate transportation of money. Colino's associates were both charged with conspiracy to transport money taken by fraud.

Colino faces a maximum of 10 years in jail and a $250,000 fine, while Manuel G. Serra, a Washington real estate broker, and Charles G. Gerrell, an Arkansas mortgage broker, each face a maximum of five years in jail and a $250,000 fine.

Under terms of the plea agreement approved by U.S. District Court Judge Gerhard A. Gesell, the three men waived their right to a trial by jury. Sentencing was set for Sept. 11. The men were released on their own recognizance and ordered to surrender their passports. Gesell ordered that they get approval of the U.S. Attorney's Office before completing any financial transactions of more than $10,000.

Assistant U.S. Attorney David F. Geneson said the investigation into the scheme to defraud Intelsat was continuing under the direction of the FBI. Jose L. Alegrett, Colino's deputy who was fired along with Colino last December after auditors identified an unauthorized payment of $1.35 million, is a major part of the investigation but is now in Venezuela, sources said.

"We do not know where Alegrett is," said Geneson. "If a grand jury charges him, we will try to seek an extradition should it be necessary." Alegrett has not been interviewed by the U.S. Attorney's Office, nor has a plea agreement been struck, he said.

Mark Shaffer, the lawyer representing Alegrett, confirmed Geneson's statements. "He {Alegrett} wants very badly to cooperate with them," Shaffer said, but negotiations are currently at a standstill.

U.S. Attorney DiGenova said the office was still in "discussions with lawyers of various parties," but declined to say who else the investigation might touch. He said the office was in the process of unraveling "basically a $4.8 million fraud scheme."

Colino declined to comment on the proceedings yesterday. A one-page written statement drafted by Colino's lawyers said his guilty plea followed "a substantial period of cooperation" with the U.S. Attorney's Office. "Mr. Colino apologizes to his family, to his friends and to the community that supported him for the pain caused them by his actions," the statement said.

Colino yesterday also filed for bankruptcy to protect his assets from creditors, which include Intelsat. In a separate motion, Colino's lawyers asked that a civil suit brought against him by Intelsat be dismissed. The suit charges that Colino funnelled millions of dollars into secret Swiss bank accounts through a complex system of kickbacks, phony construction bills and fake foreign consulting firms.

"It is simply beyond the jurisdiction of an American court" to decide a dispute between an international organization and a former chief executive relating to his conduct in office, the motion said. "We think that his motion is without merit," said Ray Banoun, a lawyer representing Intelsat. International immunity for Intelsat and its employes has been waived specifically so that Colino and Alegrett can be prosecuted and so that three dozen past and present Intelsat employes can be witnesses for the government, Banoun said.

Documents unsealed by the U.S. Attorney's Office yesterday describe four separate transactions in which Colino and his associates fraudulently obtained a total of about $4.8 million in Intelsat funds between April 1984, and December 1986. The first transaction involved the rigging of a construction contract to build an addition to Intelsat's offices at the corner of Van Ness and Connecticut Ave.

Colino and Alegrett arranged for William P. Lipscomb Co. Inc., an Arlington construction company, to win the contract by feeding the company inside information, the documents said. Colino and Alegrett then arranged for Intelsat to pay a $1.2 million fee to Lipscomb in exchange for kickbacks. Certain amounts were kept by Manuel Serra and two other associates involved in the scheme, while the remaining $1 million was sent to a Swiss bank account for Colino and Alegrett.

Next, with Serra's help, Alegrett met mortgage broker Gerrell. Gerrell, together with Serra, Colino, Alegrett and others, arranged for a phony brokerage commission to Gerrell totaling more than $1 million in exchange for Gerrell lining up $26.5 million in loans to finance the addition onto Intelsat's offices. Gerrell and others kept some of the money, while Colino and Alegrett got $250,000 -- $220,000 of which went into Swiss bank accounts.

In the third transaction, the William P. Lipscomb Co. was awarded a fraudulent contract of $1.2 million to pay for phony corrections to the original Intelsat building. Some of the money was kept by Serra and others, while Colino and Alegrett got $400,000 through Swiss accounts.

The fourth transaction outlined by the documents involved the refinancing of construction on Intelsat's original headquarters building. Colino and Alegrett used Gerrell to create false fees and expenses for handling loan arrangements. Eventually, a $1.35 million payment was made to Gerrell. He and his wife, Dana, retained $260,000, while Gerrell wired more than $1 million to Colino and Alegrett's Swiss accounts.

Intelsat lawyer Banoun said that close to $2 million of the funds had been recovered from Alegrett, Serra, German E. Perez, a close associate of Serra's, and S. Parker Oliphant, the president of Lipscomb Construction Co. Intelsat is in negotiations with Gerrell, he said. "I think we can expect the U.S. Attorney's Office to take action against Alegrett, Oliphant, Perez" and others that were involved in the scheme but did not plead guilty, he said.