It takes a real man to be in a thriller about serial killers. That’s why “”Brokeback Mountain”” star Jake Gyllenhaal must have been first on director David Fincher’s list for “”Zodiac.””

“”Zodiac”” kicks off with a couple out at a lover’s lane. It’s quiet and deserted, and it seems like the perfect place to spend time with your lady friend on a hot Fourth of July. Just before the guy (Lee Norris) can lean in and have his moment, a man drives up in a car behind them and shoots both of them.

The Zodiac killer continues on a spree of brutal killings. After each one, he sends coded letters to the police and the San Francisco Chronicle to boast about his victories. He revels in the attention he receives from the media. The police fumble around with the cases, continually one step behind in solving anything.

The Zodiac’s killings seem random, but they’re brilliant in a twisted way. Each occur in different districts, so the police are slowed down by coordination problems. None of the police departments want to share their files with each other, but each wants the glory of catching the killer.

The police detectives finally find a suspect they think fits the killer’s profile, but they get slowed down. They first have to get handwriting samples, wait to get a search warrant and jump through all sorts of hoops. By the time they’re able to go into the suspect’s trailer to search for evidence, everything is already cleared out.

With the main suspect cleared, the police have no more ideas. Many years go by with no more killings

and no more evidence surfacing; those who were involved slowly give up. The only person who actively pursues hunting down the killer is the Chronicle cartoonist (Gyllenhaal) who is obsessed with the idea that the killer is still out there.

“”Zodiac”” keeps you from ever feeling at ease. The killer strikes randomly throughout the movie, and you never know when the next victim’s coming. To raise the surprise element, he doesn’t attack when you expect it. In addition, the creepy music that’s running in the background gives you chills.

Thriller movies tend to drag in the last third of the film because they don’t know what to do after the climax. Even though all the killings have ended, Gyllenhaal’s character keeps the plotline from becoming dull. As he rehashes the case, new clues turn up where both the characters had missed it the first time. Oh Gyllenhaal ð- we wish we never had to quit you.

Robert Downey Jr., left, and Jake Gyllenhaal, right, light up the screen in the thriller ‘Zodiac.’ The movie follows a series of killings in Northern California in the late 1960s by someone called the “”Zodiac Killer.””

Robert Downey Jr., left, and Jake Gyllenhaal, right, light up the screen in the thriller ‘Zodiac.’ The movie follows a series of killings in Northern California in the late 1960s by someone called the “”Zodiac Killer.””

Robert Downey Jr., left, and Jake Gyllenhaal, right, light up the screen in the thriller ‘Zodiac.’ The movie follows a series of killings in Northern California in the late 1960s by someone called the “”Zodiac Killer.””