A TOUGH AND TENSE FILM THAT TAKES A FEW LIBERTIES

Where docudrama goes, controversy is sure to follow.

“Out of the Darkness” (9 tonight on CBS Channels 2 and 8) is a swell way to spend two hours. But is it as true as it is tough, tense and, in many ways, terrific? Once again, viewers are left in the darkness.

The historical scenario for this CBS movie is New York’s infamous Son of Sam case, in which a deranged killer named David Berkowitz committed a string of random murders in 1976-77, baffling police and terrorizing the city until he was apprehended in late summer.

CBS has made Son of Zigo.

Ed Zigo, then a New York detective, is the focus of the movie (originally titled “Zigo’s Choice”), which shifts back and forth between Zigo’s life as a cop and his life as a devoted father and husband. He was asked to join the Son of Sam task force, but turned down the career-advancing offer to spend more time with his seriously ill wife, Ann.

Filmed in New York, “Out of the Darkness” is a taut, fascinating, realistic-looking, well-acted suspense story that soars above the hokey, tire-screeching and gratuitously violent cop yarns that predominate on TV.

Jud Taylor directed the movie, which leaves you entertained, moved and with an understanding of the slow, tedious and frustrating investigative process often involved in pursuing a case like Son of Sam.

Martin Sheen is first-rate as Zigo, and there are convincing supporting performances here by Jennifer Salt as Ann and Robert Trebor as Berkowitz.

Unfortunately, “Out of the Darkness” also sometimes seems in limbo, unsure of whether it’s a love story or a police story. Although the Zigo family sequences are nicely done, they appear at times to have been injected merely to make the story more commercial.

More important, there is the question that dogs so many docudramas: Is it authentic?

Tom Cook’s “Out of the Darkness” script does note that Zigo was not present during the arrest of Berkowitz and was a late-comer to the investigation because of his wife’s illness. Yet you can easily get the impression from this movie that Zigo was a major force in the case, that he was the bigger-than-life hero of Son of Sam.

By other accounts, he was merely an 11th-hour peripheral player, happening onto the murderer’s car only because he was assigned to check out some traffic tickets.

Scores of docudramas have been found to be heavy on the drama and light on the docu. (CBS was blasted last year for its handsomely produced, but factually suspect miniseries, “The Atlanta Child Murders.”)

Docudramatists argue that their perception of history and topical events can be as valid as news accounts, which present life through the subjective prism of journalists. Often, however, docudramas conflict with established, documented fact. And yet those docudramas--because of the power of TV--virtually become the accepted historical record.

The catalyst for “Out of the Darkness” was a film treatment on the Son of Sam case by the late Phil Barnow, a highly competent Los Angeles TV newsman who earlier had covered the case as a police reporter in New York. There was far less emphasis on Zigo in Barnow’s version than in the CBS movie, whose technical adviser was Zigo and producer Sonny Grosso, a former New York cop.

There is also strikingly less emphasis on Zigo in Lawrence D. Klausner’s 1981 book “Son of Sam.”

How out of line is “Out of the Darkness?” Well, on lesser matters, the actual Son of Sam case was played out in the spring and summer, while most of the scenes in “Out of the Darkness” are snowy and wintry, sort of like “The French Connection.”

More dramatic intensity, less truth.