Alien Nation

Alien Nation began as a regular movie in theaters, then as a 2-hour pilot (tv-movie), then a tv series, then some tv-movies:

Set in Los Angeles* of the near future, 300,000 humanoid extra-terrestrials (called "Newcomers" or the derogatory "Slags") from an alien refugee slave ship decide to stay on earth and integrate themselves into human society. They've learned the language and tried to fit in. But there's something about them we don't know. When Matthew Sykes, an alcoholic and bigoted cop, is paired with one of these Newcomers to investigate a murder, they uncover a sinister conspiracy that threatens to destroy the fragile harmony between aliens and humans. The two detectives - one human, one alien - put aside their mutual distrust and uncover a trail of murder and something more terrifying.
Released October 7, 1988. Aliens makeup created by Stan Winston Studios. Director: Graham Baker, Stars: James Caan, Mandy Patinkin, Terence Stamp
* French translated title for the film is "Alien Nation futur immediat, Los Angeles 1991."

Detectives Sikes and Francisco (Gary Graham, Eric Pierpoint) deal with a virus deadly to Newcomers, and an alien emissary who wants to return the Newcomers to slavery - and take Earth's human population as well.
In the original "Alien Nation", escaped slaves from the planet of Tencton came to earth in search of sanctuary. Gradually, they won their civil rights, integrated themselves into society, and settled down. But even as many earthlings grew used to the "newcomers", splinter groups, called the "purists", resisted their entry into our world. "Alien Nation: Dark Horizon" continues the story, once again focusing on George, a Tencton who joined the police force, and his partner Matt. But now this intergalactic tale shifts into an even darker mode. The purists have developed a virus designed to harm only aliens -- and George's wife and daughter are among the first to fall ill.
But danger comes from their own kind as well, in the form of a Ahpossno, a bounty hunter from back home who wants to bring the escapees back to Tencton... where they would once again become slaves -- or worse.
"Dark Horizon" is a follow-up to Fox's 1990 tv series, Fox aired it on October 25th, 1994.

A murder exposes secret research by a Newcomer scientist with a shocking past. Gary Graham, Eric Pierpoint, Terri Treas.

Sikes and Francisco go after a cult leader (Kerrie Keane) who's using a mind-expanding artifact to lure followers, including Francisco's son Buck. Calaban: Steve Flynn

Alien Nation books are available. And videos or DVD

Other "Alien" movies including, of course, Alien (1979)