A new test given to 39 D.C. police recruits accused last week of using marijuana has found no evidence of recent drug use by most of them, and the department is now uncertain whether it will fire the recruits, Police Chief Maurice T. Turner disclosed yesterday.

Turner, who ordered the recruits to surrender their guns and badges last week after an April 5 urine test showed drug use, said the new and contradictory test results put him "between a rock and hard place" in deciding the fate of the 11 women and 28 men, who were scheduled to graduate Friday to their first full-time police assignments.

Turner said he will review the results of an internal investigation, including lie-detector tests, before deciding whether to fire any recruits. He said he planned to decide by Friday.

The new test results, showing evidence of drugs in only 13 to 19 cases, are the latest twist in a controversy that arose from the department's first use of a newly developed technique of marijuana testing. Washington is the only area jurisdiction, and one of few in the country, to use the test, which has only been widely marketed in the last year, according to drug experts.

While the chemical tests themselves are viewed as more than 95 percent reliable, according to experts, the D.C. police test has been marred by allegations of sloppy testing methods and possible mix-ups of urine samples.

Yesterday's disclosure by Turner brought a renewed protest from the Fraternal Order of Police. FOP attorney Barry C. Stiller said the new results are further indications of shoddy testing methods, and said the police department should not use either the original April 5 test or the April 26 followup exam as the basis for deciding whether to fire the recruits.

Turner, however, said yesterday he has no evidence that the tests were faulty in any way, and said he still believes he was correct to discipline the 39 recruits. He noted that D.C. law prohibits the issuance of firearms to drug abusers and said he would have been negligent to allow the 39 to continue functioning as armed probationary police officers.

Turner, seeking to explain the discrepancies in the two tests, theorized that the second urine test netted fewer marijuana users because many of the 39 probably stopped smoking the drug after the April 5 test. Therefore, he said, traces of the drug had left their bodies for the follow-up test 21 days later. The 39 recruits were retested on the same day that they were placed on administrative leave with pay.

Turner said yesterday that the urine tests detect only those drugs consumed within the last 10 days. Turner had mistakenly stated last week that the tests could detect years-old drug use, leading the D.C. police union to protest that Turner appeared to be seeking to purge even those officers who might have experimented with marijuana in their youth.

That was not his intent, Turner said yesterday. He said he authorized the marijuana test only to determine whether recruits have used drugs since they were sworn in Dec. 14 at the start of their 21-week training period.

"I don't want this police department going on a witch hunt" to find out if recruits ever tried the drug, he said, "I am not a purist about this. But I have a problem with police officers sworn to uphold the law, who could lock up people for the same offense, going ahead and doing it themselves."

He noted that the department's recruiting guidelines do not prohibit the hiring of persons who may have tried marijuana prior to being sworn in. He said young persons may have experimented with the drug in high school or college, or in military service in Vietnam, for instance, and could still be considered good candidates for police work.

The department policy, however, does not allow even single-time users of stronger drugs to be considered, according to police recruiting personnel. D.C. police recruits have been tested for drugs other than marijuana since the early 1970s.

FOP labor committee president Gary Hankins has acknowledged that 39 recruits may be guilty of marijuana use, but said the union believes the wrong 39 may have been accused. At least 35 of the accused recruits denied drug use, and several said their urine sample bottles were mislabeled, were dirty, or were accidentally switched with those of other recruits.

Stiller said at least eight accused recruits have had themselves tested privately, and all eight were negative.

"These people have been treated like lepers and outcasts, and they have been denied due process," Stiller said.

Police sources said that Turner ordered the tests after several staff members at the police academy complained about several recruits behaving in a distracted and inattentive manner. Concern about possible drug use among recruits was heightened when a 25-year-old recruit was arrested March 28 on charges of heroin possession, they said.

Turner acknowledged that he had "informal" reports about behavioral problems among recruits, but said he would have tested the recruits anyway.

Sources said the police department's top brass was shocked when 39 tests came back positive, indicating drug use by nearly one-quarter of the entire 165-member class. They said the department's lab, Abel Laboratories in Columbia, triple-checked the results to try to assure accuracy.

Police officials earlier this year acknowledged that their routine screening process of recruits had in some cases broken down, partly because the department was under pressure from Congress and Mayor Marion Barry to quickly hire 200 new officers. Three recruits were hired, for instance, but later fired for concealing criminal records.

Turner said the screening process broke down only in isolated cases and also said the current marijuana controversy should not be considered a reflection of the caliber of the current class.

"They are an excellent group of people, other than the lab reports. They look like outstanding candidates to be officers," he said.While he said he was upset by test results, he added, "I guess one has to look at society as a whole. This indicates that a substantial number of people use marijuana. Police officers are not gods, you know. They cannot walk on water, even after you give them a badge."