| Lou Karnacki | |
|---|---|
 D.A. Lou Karnacki summing up in the Otis Williams' trial | |
| Vital Statistics | |
| Title | Former District Attorney |
| Gender | Male |
| Status | Alive |
| Occupation | Lawyer in New York D.A. Office |
| Character Information | |
| Appearances | "Law & Murder" |
| Portrayed by | Bruce Davison |
Lou Karnacki was the D.A. of New York, and an old friend of Captain Roy Montgomery.
One of the major supporters of Karnacki's campaign was the wealthy Addison family, prompting them to turn to him to prosecute the case when their daughter, Lyla Addison, was killed in an apparent carjacking, offering him new funding for his next mayoral campaign if he achieved a successful conviction.
Although the case appeared to be open-and-shut when small-time street criminal Otis Williams was found joyriding in Lyla’s car, Karnacki found himself in trouble when Joe McUsic, owner of a halfway house, sent him new evidence, proving that Lyla had actually been a victim of manslaughter while out on a drug-buying drive with her brother, Stephen.
Although Karnacki attempted to conceal the evidence, concluding that the good he could do for New York outweighed all other considerations, and that nobody would miss a common "street punk", an investigation into Joe’s death while he was serving on the jury for Williams’ trial revealed the truth, prompting Montgomery to confront Karnacki in his office and demand the evidence, suspecting he hadn't disposed of it.
When Montgomery revealed himself to be wearing a wire recording Karnacki's confession, Karnacki leaped from his seat and attempted to bribe Montgomery with the position of police commissioner if his mayoral campaign succeeded. However, the captain did his sworn duty, upheld the law, and demanded the evidence once more, promising to put in a good word for Karnacki.
The resulting scandal apparently ended his career, with Castle noting how sad it was that Karnacki would be remembered for the one corrupt thing he did as the D.A. and not all the good things.