This is uk health and safety law.Hires a couple of security guards. A company can't be held to account for outsiders breaking the law can they? As long as they show they have reasonably tried to stop it from happening again there wouldn't be grounds to tear up a contract.
Lawyers are going to have fun.
Assuming that Portuguese law is the same, if the employers failed to take these steps. It looks like they failed to provide proper security.
- The Management of Health and Safety at Work Regulations 1999
Employers must consider the risks to employees (including the risk of reasonably foreseeable violence); decide how significant these risks are; decide what to do to prevent or control the risks; and develop a clear management plan to achieve this.