One final case for ‘Psych’ as finale approaches

After eight seasons of zany crimes, ‘Psych’ is closing its doors.

The cult USA Network comedy series about a faux psychic detective (James Roday) and his sidekick Gus (Dulé Hill) will air its series finale March 26 at 9 p.m., bringing the channel’s longest-running show to a close.

Though creator Steve Franks, who wrote and directed the finale, had an entire season to prepare for the episode, he says he still found it hard to craft the right ending.

“I quickly realized it wasn’t just about what makes me happy; it was as much about the fans. It’s quite a burden,” he tells The Post. “You want to stay right by them and true to what we started.”

In the series finale titled “The Breakup,” Shawn and Gus help Detective Lassiter (Timothy Omundson) enlist Henry (Corbin Bernsen) and Woody (guest star Kurt Fuller) to solve the murder of a real estate executive. The case stirs up tough emotions for Shawn, who is struggling with a big life decision.

And Franks says he is “99.645 percent sure” that he’s delivered a satisfying ending for the show’s rabid fans — affectionately known as “Psych-O’s” — that ties up all of its long-running stories, like the Shawn-Juliet (Maggie Lawson) relationship.

“I couldn’t be happier with the way that we’ve went out,” he says, pointing to final-season stunts like the penultimate episode, “A Nightmare on State Street.” “We’ve put fun at the top of importance. The last episode, there may be tears for some people and hopefully a lot of smiling and laughing by the time it’s all over.”

‘Psych’ became known for its genre spoofs — including the films of Alfred Hitchcock and the David Lynch TV series ‘Twin Peaks’— as well as a special musical episode last December, its running pineapple gag and frequent use of guest stars. Franks hopes that after 8 years, the series’ levity is a big part of its legacy.

“I hope it’s one of those shows that on a rainy day you pop in or call up on Netflix and it’s one of those things that makes you feel better, brings light into a dark day,” he says. “We were always sort of a reaction to the dark procedural when we started. We hope we honored that and made people’s outlook a little bit better.”

And while the finale will be followed by a one-hour live aftershow featuring a Q&A with Franks and the cast, it may not be a final goodbye for Shawn and Gus. USA has left the door open for a possible ‘Psych’ TV movie or special, and Franks says he still has more stories to tell should the opportunity present itself.

“I think I’ve been asking to make a ‘Psych’ feature film since the second season. I would be so into it,” he says.

“If we can get the guys back together, I think it would be a great time, we’d have a lot of fun doing it. I’d be the first person to show up on the set.”