You're confusing two different processes.
There is a criminal process, if a crime (e.g. stalking/harassment) has been committed - this will be pursued by the police / CPS.
Then there is a HR process, which will be pursued by the employer. Dismissal for gross misconduct is pretty much the maximum that an employer can do. This is totally separate to the criminal process, and the employer can apply a lower burden of proof (someone doesn't have to be successfully convicted of the crime to be dismissed).