^^ Only if you can prove motivation, as opposed to sheer ignorance. He's going to plead the "i didn't know" card, or whatever. He deserves a stern reprimand, perhaps probation. A second infraction would likely lead to termination.
Repeatedly accidentally deleting someone else's code that you don't like, is sufficient evidence of motivation. You don't have to take his word on it, you can judge from conduct ones motivation. Once can be an accident, multiple times is strong evidence that is was deliberate.
Besides, even if you accept the accidental theory, repeatedly accidentally destroying a company asset thru sheer ignorance is gross incompetence and a valid reason for dismissal. (However, if the state believes the fired employee that it was incompetence instead of deliberate they would be eligible for unemployment insurance.)