The head of the Fraternal Order of Police, the bargaining agent for D.C. police officers, yesterday criticized the department's handling of allegations that police tipped off drug dealers to a major 1986 drug raid, saying that officials made it "extremely unlikely" that the allegations would be successfully investigated.

Gary Hankins, labor committee chairman for the FOP, said the department failed to provide adequate assistance to a 4th District officer who first discovered the alleged police leaks about the failed Operation Caribbean Cruise drug sweep in February 1986.

It was the second time this week a union representing one of the city's uniformed services criticized the police department, which is beleaguered by a wide array of allegations of wrongdoing. On Wednesday, the D.C. firefighters union asked Mayor Marion Barry to halt drug testing of firefighters because of allegations by two police employes at the Police and Fire Clinic that officials at the clinic were engaged in "a systematic effort to subvert the integrity of the drug testing procedures."

Former deputy chief James P. Shugart said Tuesday that the Caribbean Cruise investigation was handled by Officer Curtis H. Arnold, a 17-year member of the force, who could not substantiate the allegations and failed to forward them to the department's Internal Affairs Division, as he had been ordered to do. The officer's friends and associates say he was actually ordered to drop the investigation and destroy tapes he had made as part of his probe.

Hankins said the investigation of leaks should have been handled by internal affairs from the beginning, since it is the unit that usually probes allegations of police misconduct.

He said, however, that once it was decided that the investigation was to be handled by Arnold, the officer should have been given adequate support -- such as an undercover car, money to pay informers and additional manpower -- but wasn't.

"Given the magnitude of the circumstances and the allegations, it's difficult to understand why, against the department's policies and procedures, they decided to have a single {4th} district investigator without any additional resources conduct the investigation," Hankins said.

"They created the circumstances that made it extremely unlikely that any detective could have successfully investigated the allegations," Hankins said. "They said, 'You will investigate this alone; you won't have the support of {internal affairs} or the expertise of their surveillance.' What do they think internal affairs is, a potted plant?"

A police spokesman said the department had no comment.

The FBI is investigating allegations that at least three 4th District officers leaked information about Operation Caribbean Cruise to suspects in the raid, which was designed to net hundreds of arrests and huge caches of weapons and illegal drugs but yielded only 27 arrests, $20,000 in drugs and 13 weapons.

The FBI is also investigating allegations that some members of the 4th District vice squad kept drugs and money that they seized during raids. All squad members have been reassigned since the probe was reported in The Washington Post on Aug. 27.

The U.S. attorney's office has announced that it will drop 300 to 400 pending drug cases investigated by members of the squad, largely because prosecutors suspect that officers frequently lied in the process of obtaining search warrants connected with the cases, sources have said.

Some sources claim that the department had specific information about Caribbean Cruise leaks -- including tapes of secretly recorded conversations with dealers identifying officers who they alleged had tipped them off -- but that the department did not adequately pursue the information.

Other current and former high-ranking police officials claim that Arnold, who made the tapes, was not able to substantiate the allegations and never turned the information over to internal affairs to follow up.

In his comments yesterday, Hankins emphasized that the FOP believes that the officers accused of leaking information about the raid and of skimming drugs and money should be presumed innocent.

Nonetheless, he echoed the private comments of others in the department who have questioned the decision of Police Chief Maurice T. Turner Jr. to have a 4th District officer investigate his colleagues, noting that that duty would ordinarily fall on internal affairs, which previously had investigated the leaks without success.

Sources said that it was highly unusual for an officer to investigate someone of his own rank -- which is what Arnold did -- noting that that is one reason internal affairs is staffed by persons no lower than the rank of sergeant.

On Tuesday, Shugart said the investigation was given to the 4th District because it was determined that the informants whose conversations Arnold had recorded would talk only to him and not to anyone from internal affairs.

However, sources said the usual procedure would have been to detail Arnold temporarily to internal affairs, where he could pursue his sources while the watchdog unit offerred assistance and helped guide the investigation.

Hankins accused the department yesterday of "circling the wagons" on the question of whether Arnold was ordered to turn the investigation over to internal affairs, and he accused Shugart of making "self-serving statements" on the issue.