Amidst the first stirring of apprehension by some forensic psychiatrists and civil libertarians, an increasing number of police departments and prosecutors' offices across the country are training their own hypnotists to interrogate consenting witnesses and victims in hard-to-break criminal cases.

While proponents of the technique claim it is safe and reliable aide to criminal investigation, some experts in hypnosis argue that information elicited from a witness who has been put into a trance is of questionable legal value, at best, and frighteningly Svengalian, at worst.

Robert Reiff, a psychologist who has published work on experimental hypnosis, asked the Justice Department to stop its Law Enforcement Assistance Administration from promoting seminars at which police officers and district attorney staffs are taught how to use hypnosis to enhance witnesses' recall about crimes.

The LEAA helped advertise and promote a law enforcement hypnosis seminar last week in Los Angeles at which 50 law enforcement officers were trained in the use of hypnosis. It was the second such national training seminar held in a year by the Law Enforcement Hypnosis Institute of Los Angeles.

"Such a powerful suggestive technique in the hands of law enforcement personnel poses a serious threat to the rights of offenders and victims," Reiff, an official of the American Board of Psychological Hypnosis, an accrediting board for medical hypnotists, said in a telegram to Attorney general Griffin B. Bell.

"This practice borders dangerously on the methods characteristics of the law enforcement systems of totalitarina countries," he added.

Recently, the most extensive use of law enforcement hypnotism has been in the Los Angeles Police Department, where psychologist Martin Reiser, who conducted last week's police seminar, pioneered the technizue in 1970.

Reiser, head of the LAPD's Behavioral Sciences Division, said his officers have used hypnotism in several hundred cases and that in 60 to 65 per cent police elicited information that helped solve major crimes.

Last July the FBI called in William S. Kroger, an expert in medical hypnosis, to interrogate the driver of a school bus in Chochilla, Calif., who with some students, had been kidnapped by three men. In a hypnotic trance, the driver, Ed Ray, recalled all but one digit of the license plate of the of the kidnappers' van; the information helped authorities track down the suspects.

In another case, a woman who had been high on drugs could recall no details of the murder of her boyfriend; however, in a hypnotic trance she gave police a detailed description of the assailant, which led to the arrest of the killer.

Reiser, in a telephone interview, said he believes the psychological discipline is just beginning to pay dividends.

"It's a developing field. More and more police departments are interested in adding this technique to their investigative tools," he said. "I predict that within the next 10 years hypnosis will become a standard tool of law enforcement."

Already, he said, the technique had been taught to police officers from New York City; Denver; Phoenix; Indianapolis; Boulder; Colo.; San Antonia; the Air Force Special Investigation Unit; the Treasury Department's Bureau of Alcohol, Tobacco and Firearms, the FBI and numerous state police departments.

Yet Reiff warned that police hypnotists could influence courtroom testimony with posthypnotic suggestions that the witness "positively identify" suspects that the police wished to be to so identified.

His claim was considerably stronger than those of some other experimental psychiatrists interviewed, who based their objections more on the prospect of a mesmerized witness fantasizing or making mistakes while in a hypnotic trance.

One of them, Martin T. Orne, director of experimental psychiatry at the Institute of the Pennsylavania Hospital in Philadelphia, said improper questioning under hypnosis could cause a subject to distort his memory of a crime.

Also, Orne said, hypnotized witnesses are susceptible to creating visual descriptions that either never existed, or, worse, reflect what the witness knows or can guess about what authorities think about a crime.

"If I hypnotize you and tell you the year is 1983 and you are standing in the middle of Times Square and I ask you what is happening, you might describe a scene in great detail," said Orne, who is considered preeminent in his field and has testified in numerous criminal trials, including the Patricia Hearst case.

In any event, Orne said, a hypnotized witness or crime victim should never be permitted to testify at a trial without a videotape of the entire interrogation session to establish the quality of the technique.

He said he recetly testified in a trial in which the witness' testimony mand the videotapes were ruled inadmissible by the court.

"If a hypnotist has an ax to grind, he can very easily impart critical information to his subject. He [the witness] is now of no further use as an objective witness," Orne said in a telephone interview.

Anytime a hypnotized witness is used in a trial. Orne proposed, the jury should be made ware of the risks involved and all data from the hypnotic session should be made available to defense counsel for scrutiny by competent scientists.

Reiser claimed that hypnotized witnesses are credible in court because more and more judges "are recognizing this field as a legitimate process of discovery." The weight of testimony, he said, most California juries have been disposed to accept such testimony.

"We don't interrogate suspects with hypnotism, only witnesses and victims who voluntarily submit themselves. The issue of rights doesn't really come into play," he said.

New York City Police Detective Sgt. Charles Digget, assigned to the Brooklyn homicide squad, attended last week's hypnosis course and said, in an interview, that the technique can be valuable to solving major crimes.

"We used it in 20 cases and in 80 per cent of them we elicited new and valuable information that we couldn't have obtained otherwise. I think it's a fantastic possibility," Digget said.

Despite these apparent successes, hypnosis experts such as Orne still have reservations.

Orne was critical of LEAA promotion of law enforcement hypnosis, saying, "Unfortunately, hypnosis is seen by the police as a magical solution. This view needs to be corrected."