The second half of CSI's first year takes Grissom and his untiring team down some darker paths than before. Nick finally gives in to his urges and sleeps with the hooker who has a crush on him in "Boom"--with predictably disastrous consequences. Sarah is badly affected by the rape and attempted murder of an unknown woman in "Too Tough to Die"; and even Grissom is shaken when dealing with the sudden death of an infant in "Gentle, Gentle". The final episode of the year, "Strip Strangler", is a real shocker, as the team track a brutal serial killer.

Elsewhere, the morbid business of investigating corpses and crime scenes is enlivened with flashes of welcome humour: when a horse is found dead with packets of uncut diamonds concealed in its uterus, Grissom deadpans "This horse is a mule". Throughout, the show remains focused on its scientific remit, only revealing enough of the characters' private lives to provide added piquancy to each investigation: Sarah's complete lack of a life outside her work; Warrick's old gambling habit; Catherine's attachment to her daughter and troubles with ex-husband Eddie; Nick's over-eagerness to please. Grissom, meanwhile, like the Dalai Lama, is the model of inscrutable wisdom. The show itself, like a millennial antidote to a decade of X-Files, is relentlessly empirical: everything that initially seems mysterious--from spontaneous human combustion to an apparent case of vampirism--is always explicable and explained by the team's scientific dedication.

On the DVD: CSI, Series 1 Part 2 contains 11 episodes on three discs. Extra features consist of a brief promo featurette, production notes and a series of on-set interviews with the cast. Oddly for such a cutting-edge show, picture is old-fashioned 4:3 with basic Dolby stereo sound. --Mark Walker

The latest in a long line of successful US police dramas, the forensic cop show Crime Scene Investigation varies the formula by focusing on a team of civilian scientists who work the night shift in Las Vegas, poring over crime scenes for fingerprints, blood spatters, DNA-laced mucus and (especially) maggots.

Star William Petersen plays a variation of his role from Manhunter, the cool puzzle-solving genius who can rattle off mystifying speeches with aplomb, while his contrasting partner is Marg Helgenberger, cast as a single mother/ex-stripper who is as concerned with the emotional as well as the physical mess left by crime.

While most US cop shows (witness NYPD Blue) tend towards soap, neglecting the cases in favour of personal crises, CSI gives its regulars enough life to make them human but is essentially puzzle-based, with individual episodes following two or three cases à la Homicide: Life on the Street. The occasional special focuses on a major job with the team investigating the slaughter of a whole family ("Blood Drops") or a death in first class on a plane over Vegas ("Unfriendly Skies"). A few continuing threads are laid down, with a recurrent villain who gets away, but will inevitably return, but on the whole these shows play pretty well as one-offs. Very high-tech in style, with lots of zooms into microscopic examinations of hair follicles or stomach contents and distinctive visualisations of the different stories told by witnesses and evidence, this is one of the best shows currently airing.

On the DVD: CSI's first DVD box set contains the show's first 12 episodes: the pilot followed by "Cool Change", "Crate & Burial", "Pledging Mr Johnson"; "Friends and Lovers", "Who Are You?", "Blood Drops"; "Anonymous", "Unfriendly Skies", "Sex Lies and Larvae"; "The I-15 Murders" and "Fahrenheit 932". In addition to inventive menus, the three-disc set offers character profiles, a trailer, some B-roll on-set footage, a subtitle option, and snippet-like interviews with the cast and creatives. --Kim Newman

These first 12 episodes from the second series of CSI: Crime Scene Investigation consolidate the show's well-deserved popular appeal, while beginning to explore (gently at first) beneath the slickly professional surface of the investigators themselves. Gradually we learn more about what makes Grissom and his astonishingly gifted forensics team tick, beyond merely that they're workaholics who seem to require no sleep at all.

The show's trademark reveals of vital evidence--be it on the autopsy slab or under the microscope--add a fresh spin to what is, at heart, a good old-fashioned whodunit series. William Petersen brings the requisite air of antiquarianism to a character whose meticulous demeanour and love of order consciously inherits the mantle of Sherlock Holmes (whose vast collection of tobacco samples and bottles of chemicals are the ancestors of CSI's high-tech crime lab). This is a series in which scientific evidence-gathering is elevated to the status of a religion. "When a tree falls in the forest, even if no one is around to hear, it does make a sound", affirms Grissom with the calm assurance of a yogi on the path to Enlightenment.

And just when CSI starts to seem a little too pat, just when the trail of clues seems too neat, the show always seems able to throw a surprise or two at us: perhaps there has been no crime after all; perhaps the evidence concerns a completely different crime altogether; or perhaps, as in one brave episode concerning brothers implicated in multiple murders, the evidence simply isn't good enough to convict the right man, even when Grissom knows which one really is guilty. As a result, every episode is simply compulsive viewing.

On the DVD: CSI: Crime Scene Investigation, Series 2 Part 1 comes in a three-disc set with several worthwhile extras. There are cast and crew interviews, an on-set tour, a peek at the workshop where all the bloody body parts are created, and, most informative, selected episode commentaries featuring writer-creator Anthony E Zuiker and director and producer Danny Cannnon among others. Picture and Dolby Digital sound are impeccable. --Mark Walker

Thanks to its focus on more single-case episodes, the second half of CSI's second series is an even more highly concentrated dose of forensic puzzle-solving from the Vegas science sleuths. With the whole team working together on one puzzle crime (or series of crime puzzles), the group dynamic is elaborated and the audience drawn deeper into each investigation. The first three episodes are all single cases: "Identity Crisis" sees the return of Grissom's nemesis, serial killer Paul Millander; in "The Finger", Catherine is caught up in an elaborate kidnap plot; while in "Burden of Proof", a stray body in a "body farm" leads to a difficult case of child abuse. After a brief return to the two-investigation-per-episode format, the team unite once more for one of their most intriguing cases, "Chasing the Bus", in which they must unravel the mystery of a bus crash in the desert. "Stalker" is possibly the show's most terrifying episode to date, with a woman found murdered behind the safely locked doors of her apartment.

The season concludes with "Cross Jurisdictions", a rather unsubtle way of introducing the spin-off show CSI: Miami and, finally, "The Hunger Artist", a somewhat strained attempt to comment on our society's obsession with glamour and self-image, which is most notable for Grissom's devastating discovery that his hearing problems are not only congenital, but irreversible. --Mark Walker

Now firmly established as the top-rated US drama, by its third year CSI: Crime Scene Investigation is a show positively glowing with confidence. Even when individual cases seem either too contrived or too easily resolved, the indefatigable night shift at the Las Vegas PD crime lab always look the part, solving conundrums and discovering microscopic damning evidence while, apparently, never shedding their own loose hair or skin cells all over the supposedly quarantined crime scenes. In reality, Catherine Willows' flowing blonde locks would contaminate any evidence she collected, but in the world of CSI only the bad guys leave body parts behind--the CSIs themselves are so good they're positively pristine.

The first 12 episodes of season 3 on this three-disc set present more deliciously bizarre situations for the problem-solving sleuths: cannibalism, snuff movies, dwarfs, death while drag racing, bodies falling from the sky, and various dismemberments all tax the team's acumen. These are all double or multiple-case episodes, though in a characteristic trick of the writing sometimes apparently unrelated murders turn out to be connected (or vice versa, as in "Blood Lust", where a road accident victim is not what he seems, and the death of the driver at the hands of an angry mob is made all the more tragic.) The mix of genuine forensic science with the glossiest Jerry Bruckheimer production values, plus the virtues of a good ensemble cast headed by William Peterson's modern-day Sherlock Holmes, remains as compelling as ever. --Mark Walker