Even though Mark is no longer a detective, he still uses his police skills to investigate high-profile cases, like the 1975 murder case of Martha Moxley.
Thirty-five years ago, 15-year-old Martha was bludgeoned to death in her upper-class neighborhood of Greenwich, Connecticut. While the police investigated, they made no arrests—until new evidence was uncovered 27 years later.
This new evidence included information Mark found and lead to the arrest of Ethel Kennedy's nephew, Michael Skakel. "If you're not courageous enough to go up against some of the richest families in the country, then it's not going to be solved," Mark says. Through solid police work—conducting interviews, taping conversations, uncovering lies—Mark says he helped put together a puzzle just as he had done in the O.J. Simpson case years earlier.
Except this time, Mark's work paid off. Michael Skakel was convicted of Martha Moxley's murder and sentenced to 20 years to life in prison. Though he believes that this trial and the O.J. Simpson trial are mutually exclusive, Mark says the Skakel conviction was gratifying, especially in the wake of O.J.'s acquittal.
"I think I did pay a debt [to society]," he says.