BY day, Dr. Stephen Kinzey was a respected, tenured professor, loved by his students and well thought of by his university colleagues. But by night, U.S. cops claim Kinzey lived a secret shadow life as the drug-dealing, gun-toting leader of an outlaw biker gang called the Devil’s Diciples (sic).

    When police raided the well-tended, Spanish-style home that Kinzey shared with his beautiful blonde girlfriend in an upscale California community, it looked like an episode of TV’s “Breaking Bad,” in which a school chemistry teacher gets sucked into a dangerous double life as a crystal meth dealer.

    San Bernardino detectives seized more than 500 grams of methamphetamine, hand guns, rifles, a shotgun, brass knuckles, body armor, cash, leather gear with gang colors and Nazi SS insignias — plus a black jacket bearing the name “Skinz,” the name Kinzey goes by in the biker world.

    That bust at the HQ of Kinzey’s alleged drug empire — and his subsequent arrest — came three years ago almost to the day.

    When Kinzey was arrested Aug. 26, 2011, it sent shock waves through the sprawling campus of Cal State University in San Bernardino, where, for more than a decade, Kinzey, 48, taught kinesiology, the science of human movement.

    And his arrest stunned the mild mannered professor’s neighbors in the quiet, tree-lined section of nearby Highland where he lived with his girlfriend Holly Robinson, his alleged partner in a meth dealing operation that police say raked in big bucks.

    “I was shocked,” said one neighbor who recalls Kinzey having occasional visits from friends on motorcycles, but no rowdy parties or trouble. “He always seemed like a nice, friendly person.”

    Kinzey’s father, Hank Kinzey, 69, who lives near Detroit, described Stephen — who was fired from his Cal State teaching job in December 2012 — as a good Catholic and a good father who doesn’t drink and doesn’t smoke. “I believe my son is innocent and this is all a huge mistake.”

    But police insist there is no mistake — that quiet, reserved Kinzey, who has a 17-year-old daughter from a failed marriage, is indeed a wolf in sheep’s clothing, they allege.

    “One side of him was a successful and productive member of society, but the other side of him is an outlaw motorcycle gang leader,” San Bernardino County Sheriff’s Sgt. Paul Wynn — a lead investigator in the case — said after Kinzey’s arrest.

    When Skinz allegedly turned out to be Professor Kinzey — who has bachelor’s, master’s and doctorate degrees and chaired several academic committees at Cal State — even the cops found it hard to believe at first.

    Kinzey faces five felony counts: possessing drugs while armed, participating in a criminal street gang, possession of drugs for sale, conspiracy to sell drugs and receiving a stolen gun. Kinzey — who is pleading not guilty to all the charges and has been free on US$300,000 bail — is looking at up to 20 years behind bars if convicted. (SD-Agencies)