"Apparently it's illegal to have an unregistered assault rifle in Southern California," said Leben, chuckling. "That was my bad."
Knowing the troubled life of one of MMA's most prolific bad boys, it isn't altogether surprising "The Crippler" spent a spell in the Big House.
What is surprising is the fact he's come out with a tell-all book about his life entitled, The Crippler: Cage Fighting And My Life On The Edge (co-written with Daniel J. Patinkin).
The book discusses "heavy" parts of his life including his involvement in street brawls, battle with depression, along with his publicized on-again off-again struggles with alcohol, crack, opiates and self-harm.
"A little bit of it is a 'what not to do' but it's a struggle, you know? And no matter what I was going to do outside the cage I always get back on the horse, I somehow keep going and I think I'm a slight inspiration in some ways from that aspect," said Leben laughing at the idea.
But Leben is definitely not a role model, he is quick to add.
So, why write the book?
"Part of recovering is you need to own up, you need to man up to the things that you've done and the mistakes that you've made... there's definitely a therapeutic aspect to being able to own it and OK now I need to move on."
The book is heavy but it's not all doom and gloom. "Crippler" writes about his career high of knocking out PRIDE legend Wanderlei Silva and his time on the debut season of The Ultimate Fighter.
Those who watched Leben's career know how tough he is to put away, going full out in each fight until he's either knocked out or choked unconscious. And sometimes not even that is enough.
In the book he recounts his 2003 amateur bout in which he was choked unconscious by Otto Olson but the referee didn't catch it. Leben says he "had a dream" during the fight, woke up and then knocked Olson out.
Leben went 22-11 in his MMA career with 12 knockouts, retiring in December of 2013 following his fourth consecutive loss.