Sixty pounds of cash found in a green garbage bag may be part of the loot from the December theft of $11 million from the Sentry Armored Car-Courier Co. in New York, the FBI said yesterday.

The bag turned up Monday in the Westport, Conn., home of Thomas Skiados, father-in-law of the chief suspect in the heist, Demetrious Papadakos. The FBI still is counting the money.

A former Sentry security guard and three of his friends are in custody in the case. Three executives of the firm are charged in an apparently unrelated theft involving an additional $100,000. Another $729,000 is missing in three other heists at the company.

It began Dec. 12, when Christos Potamatis, 24, a dispatcher at Sentry, shouted from inside the building that the place had been robbed. Three masked men, he said, had cut through the tin and tar-paper roof late that night while he was the only one there.

He said they overpowered him and scooped up bags of cash from the office floor outside the company safe, which was too full to hold them.

The men loaded the bags into a waiting van, leaving behind millions of dollars that wouldn't fit into the van, according to Potamatis' story.

Sentry kept operating, carrying as much as $70 million a day between New York businesses and various banks. On Dec. 29, a bag containing $225,000 was stolen. The Bronx district attorney's office handled that case, since no bank was involved, and discovered during the investigation that $100,000 had been skimmed from earlier receipts.

In mid-January, police arrested the three executives on charges of misappropriation, embezzlement and larceny in the $100,000 case: President John Jennings, 64, a retired New York police lieutenant; Vice President Angela Fiumefreddo, 45, and board Chairman Kuno Laren, 58. All are free on bail.

Going through 12 crates of company records, police discovered that another $500,000 had been taken earlier from half a dozen customers' shipments. A grand jury is hearing charges in that case.

Meanwhile, the former guard, Potamatis, was arrested Feb. 2 while vacationing in Puerto Rico and was charged in the $11 million heist. In New York, the FBI arrested Potamatis' friend, George Legakis, 21, a college senior.

According to New York FBI spokesman Joseph Valiquette, Legakis then fingered two others: Eddie Argitakos, 23, a former Queens tourist agent, and Papadakos, 35, who was arrested Friday in Miami.

Valiquette said warrants have been issued for a fifth suspect, a man Legakis knew only as Nick.

Meanwhile, someone who apparently had a key walked off with about $4,100 in typewriters, desks and other equipment from the Sentry offices. "We're not even looking at that one yet," said Bronx District Attorney Mario Merola.