Given what legal defenses they are already attempting, they certainly could - and we see that a lot in criminal trials, notably in the press and in made-for-tv docudramas, murder trials.
The issue here would be what they would accuse each other of, in their separate trials. In the criminal ones, they would be looking to sow legal doubt, or specifically reasonable doubt, and accusing the other person of committing the crime is one way to do it.