Warning if you haven't watched the second season of The Jinx you should not read this, because it's a total spoiler.

When Durst is cross-examined in the trial, the prosecutor asks a series of questions that got him to admit that if he had actually killed his first wife, he would have lied in his testimony. He asked a whole bunch of things but stopped short of asking the question that would have nailed him.

Mr Durst, would you kill someone to avoid being convicted of killing your wife?

From what we know of Durst he would have had a hard time saying no. When he's caught he generally admits he's caught.

They got the conviction anyway.

PS: I don't recommend either season but having watched the first, I was kind of committed to watching the second. He's a truly despicable character.