Undercover drug agent-turned-actor makes a career of playing people he used to chase. BY BARRY KOLTNOW - The Orange County Register It was little Louie Diaz's first day of school, and his beautiful, loving grandmother was getting him ready to leave the house. She made sure his clothes were clean and neat, his hair was combed perfectly and his shoes brightly shined. She then kissed him goodbye, gave him a warm hug and sent him off to first grade with a few grandmotherly words of advice. "Now remember, Louie," she said with the tenderness and love only a grandmother could give a small child, "you don't snitch on nobody. "And if you get in a fight at school, you don't come home crying. If the boy is bigger than you, you pick up the first thing you can find and even the score." So little Louie skipped off to first grade, and he didn't snitch, he didn't cry and he always evened the score.

A warm smile filled Diaz's face as he related that story recently in the kitchen of his Costa Mesa home. The story is more than a fond remembrance of a woman who almost single-handedly raised him until age 7. In fact, it goes a long way toward explaining why Diaz is featured in tonight's episode of "NYPD Blue" (KABC/7 at 10). Diaz, 55, grew up in the brutally tough Red Hook section of Brooklyn and his grandmother's advice helped to keep him strong. He resisted a life of crime, but he had no trouble surviving among the criminals. That ability to act tough in an area infested with tough guys served him well later in life as an undercover drug agent, and it certainly has helped him in his second career as an actor.

"You look at Lou and his face spells tough New Yorker in a big way," said Bill Clark, a former New York City police detective and one of the executive producers of "NYPD Blue." "He was perfect for this role because he looks like the real thing. He doesn't seem like an actor playing a role; you get a certain organized crime hit off him." In tonight's show, Diaz plays a colorful hit man who tangles with Sipowicz (Dennis Franz) in several scenes. "It can be intimidating walking on to a set and facing a guy with four Emmys," Clark said-of Diaz's first day of shooting. "But at no point was Lou intimidated."

Perhaps he remembered his grandmother's advice. "I loved her for many reasons, but her advice was sound," Diaz said. "She knew that if you wanted to play ball on the street, you had to be a tough guy. You had to be able to defend yourself If not, you were meat." Diaz, who acts professionally under the name Lou Casal said the only thing that separated him from the guys in his neighborhood who turned to a life of crime (notorious mobster Joey Gallo was one of them) was the love shown him by his family. His family was of Basque origin (northern Spain), and his grandmother had to raise him because his father was in the Merchant Marine and his mother also worked away. "There was always a lot of love in my house," he said. "Even though my father and I didn't get along a lot of the time, I knew he loved me. He was a hard-working guy and he just wasn't around that much." Diaz went to college for a while but dropped out to join the Army. After his discharge in 1966, he worked as a telephone lineman but quit after being shot at while working on a telephone pole. He worked as a warrant officer but dreamed of being a New York City police officer. Unfortunately, at 5-foot-7, he was an inch too short to meet the height requirements then.

After returning to college, where he earned an associate degree, he met a U.S. Treasury agent who suggested he apply for a job with the Bureau of Alcohol, Tobacco and Firearms because the federal government had less-stringent height requirements. Because he spoke three languages (English, Italian and Spanish, all picked up on the street), he was assigned to undercover work. He stayed three years before beginning a 22-year stint with the federal Drug Enforcement Administration, most of which was spent in undercover work. Known in the agency as Louie the Actor (a moniker given him when he was a kid acting out movies but engraved on him for his way of acting like one of the wise guys he was investigating), Diaz said he was responsible for smashing some of the biggest drug rings in New York. "I loved undercover work," he said. "I loved the adrenalin rush from being in those dangerous situations. Frankly the danger was a high. "But I also felt comfortable in those surroundings. It was like being back in the old neighborhood, only I was on the right side." There were moments that were not always comfortable a firefight outside a cocaine lab in Bolivia comes to mind but Diaz said he was rarely afraid.

"The closest I came to dying was one night in the Ali Baba Club in New York, when I was meeting this drug guy in the men's room. As I was latching the door, I heard the slide on his gun and knew I was in trouble. I turned around and he put the gun to my head. He said, "You better not be a cop," and I said, "if you feel that way, you might as well just pull the trigger." "I didn't know fear in those days," he explained. "Fear comes from the unknown, but I knew these guys. I knew the rules they played by, and I felt comfortable being around them." Diaz said he eventually grew tired of the "rush" and started thinking about getting out. Fortuitously, he was walking in downtown Los Angeles one day when he stumbled across a movie set. He met Paul Sorvino and another actor who invited him to hang out in a restaurant that attracted a lot of Italian actors and directors. One director cast him in the 1992 movie "Maniac Cop III Diaz quit the DEA and took up acting. The roles have been mostly small, and he is always cast as a tough guy. "I've got to be honest; I'm not sure Lou is ever going to be cast as an Irish priest," said Clark of "NYPD Blue." "There are elements of typecasting in this business, and Lou might be stuck." Diaz said he knows he's been typecast, but he hopes that will change once Hollywood gets to know him a little better. "I love acting because it fulfills this burning desire inside me to express myself. And it allows me to relive my past without worrying if a guy is going to stick a real gun to my head. But this is a real tough business. I go up for auditions two or three times a week, and they see me as only one thing. "All I need is that one break. I need one person to give me a chance to show what I can do. I can show a loving, compassionate side. That's the real Louie. I'm more than just a tough guy. BY BARRY KOLTNOW The Orange County Register