Any time anyone in the workplace touches another person inappropriately, it is grounds for filing a police complaint. Some bullies go from excessive verbal abuse to physical attacks, shoving, or hitting. Once the bully touches the victimized employee, that employee must report it to the proper authorities.
In some workplaces, the proper authorities may be a security force that is part of the company, while in others it will be the local police. Make no mistake, your employer will not be happy if you bring in the police, but it is against the law to be inappropriately touched by anyone. In addition, many state laws specifically require that employers keep their employees safe from physical attacks.