The D.C. police department's Internal Affairs Division was told by police officers last year that a fellow officer who is currently a subject of the FBI's investigation of alleged police corruption may have tipped off drug dealers to a massive drug sweep, sources said.

The information about the possible leaks concerning Operation Caribbean Cruise, the drug crackdown last year that was a highly publicized failure, also was given to D.C. Police Chief Maurice T. Turner Jr., the sources said.

In addition, Turner and the Internal Affairs Division were told that some 4th District narcotics officers were skimming drugs and money from drug raids, according to the sources.

But when Turner and the Internal Affairs Division seemed -- in the opinion of the officers -- to take no action on the allegations, the officers took the information to the FBI. The bureau subsequently launched its own undercover probe of some 4th District vice officers, which culminated Wednesday when federal agents, armed with grand jury subpoenas, searched the vice squad's office on upper Georgia Avenue NW and seized a vanload of documents.

It has not been previously disclosed that the 4th District officer, identified as Shelton D. Roberts, was linked to the alleged Operation Caribbean Cruise leaks.

Capt. William White III, a police spokesman, said Turner had no comment on the FBI's probe and allegations concerning Operation Caribbean Cruise.

Turner, in an interview Aug. 26, said the Internal Affairs Division had been unable to prove allegations of leaks to drug dealers. "We still have some aspects of that investigation that are currently being conducted and it wouldn't be fair of me to comment on those," he added.

Sources said yesterday that Roberts, a subject of the FBI's investigation, was identified to Turner and Internal Affairs as one of the officers who allegedly leaked information about the Feb. 22, 1986, Caribbean Cruise operation.

The sweep was billed then as the city's largest drug crackdown, aimed at what was described as a heavily armed network of Jamaican drug dealers. But despite the participation of 550 officers and support personnel, the coordinated raids yielded only 27 arrests, $20,000 in drugs and 13 weapons.

Roberts and his partner James Whitaker Jr., who also is being investigated in the skimming probe, had their police powers revoked late Wednesday, a disciplinary action one step short of suspension. They also were required to turn in their badges, identification folders and service revolvers, sources said.

The officers, both 17-year veterans of the D.C. police department, were placed yesterday in positions in which they will not come into contact with the public, according to the sources.

Roberts could not be reached for comment yesterday. G. Allen Dale, who is representing Whitaker, said last night, "We maintain his innocence . . . and we are confident that any investigation will exonerate" him.

Officials have said that other narcotics officers in the 4th District vice squad also are under investigation for allegedly skimming drugs and money seized during raids and arrests and falsifying official reports. Sources said that in some instances, as much as $5,000 was allegedly stolen.

Investigators also are trying to determine whether the officers pooled drugs and money confiscated during several raids and then divided the proceeds among themselves.

Sources also said yesterday that a quantity of marijuana was seized during the FBI search of the vice unit and that authorities do not believe the drug was being held for evidence in a drug case.

The FBI has been examining search warrants issued to 4th District narcotics officers to determine whether any of the affidavits filed to obtain the warrants contained fraudulent information and whether any unauthorized changes were made, sources said. There are also allegations that officers executed some warrants after their court-ordered deadlines had expired, but indicated on official reports that the searches had been made at the proper time.

Officials are also investigating whether drugs obtained in the alleged skimming were used by the police officers to pay off their informants or given to the informants so they could claim that they had purchased the drugs from dealers.

In addition to Whitaker and Roberts, sources have said three or four other narcotics officers in the 4th District are under investigation. The FBI probe is limited to the 4th District, which includes sections of upper Northwest and Northeast Washington, but similar allegations have been directed at officers in other police districts.

Narcotics officers from the 4th District have executed about one-third of all drug search warrants issued by D.C. Superior Court and U.S. District Court since January. Of the 303 4th District warrants, Roberts has executed about half.

At least two accused drug dealers have claimed in court papers that Roberts stole money from them during police searches of their homes.

In papers filed yesterday, defense attorney Allan M. Palmer broadened his attack on Roberts' credibility, claiming that in addition to stealing more than $1,000 from his client, Anthony B. Fultz, Roberts failed to identify himself before breaking down the door to Fultz's home on June 16. Fultz maintains that someone shouted "this is the Bear baby" before entering. Roberts is sometimes called Sugar Bear.

Palmer also submitted to the court a bank statement showing that Fultz had withdrawn $500 from his bank account the day before his Taylor Street NE apartment was searched.

In papers filed in D.C. Superior Court, attorney James W. Robertson has complained that Roberts and Whitaker seized $16,500 in cash from his client, Dennis G. Duncan, during a search of Duncan's Marietta Place NW residence on Feb. 7, 1986, but reported taking only $14,960.

Fultz is awaiting trial on cocaine distribution and other drug charges. Duncan pleaded guilty to possession with intent to distribute marijuana.

The FBI also is investigating whether the police Internal Affairs Division covered up earlier reports about skimming. Division officials accompanied FBI agents during the search Wednesday of the 4th District vice office, and the division is now assisting in the probe.

A spokeswoman for the Coalition Against Operation Caribbean Cruise, a loose-knit group of Jamaicans who are suing the D.C. police over the drug operation, said yesterday that the coalition has voiced many of the same complaints about irregularities in police operations, specifically Caribbean Cruise.

"We cried coverup way back then," said Dera Tompkins, the coalition's coordinator. She questioned many of Caribbean Cruise's tactics, including the police department's use of supposedly controlled drug purchases by police informants. In many instances, Tompkins said, the informants were provided little supervision in carrying out the purchases.

Almost immediately after the Caribbean Cruise sweep, in which 69 homes in Northwest and Northeast Washington were searched simultaneously, D.C. police officials said they believed that information about the raids had been leaked to the suspects in advance.

In addition, a source with the U.S. Park Police, which also participated in Caribbean Cruise, said his department had turned over information to the D.C. Internal Affairs Division about a stolen 4th District police radio that was allegedly provided to a raid target. Such a radio can be used to monitor police communications.

Two months after Caribbean Cruise, Mayor Marion Barry said an internal police investigation had pinpointed the source of the leaks but that he and Turner had decided not to make the findings public so as not to jeopardize future operations.

Turner said later that the department had closed its investigation without identifying the source of alleged leaks. A police source said yesterday that the internal probe was reopened last year when the department received new information about the alleged leaks. Staff writer Victoria Churchville contributed to this report.