Your employer is not actually responsible for securing your personal property at work (the law does not make person or business A responsible for the property of person B)--they are not liable for what happens to it unless you can *prove* that they actively or actually did something to cause its loss (like tried to ship it elsewhere and lost it in the process). Without evidence or proof that the employer did something to or with your property, they are not resposible for what happened to it. Just because the property was there when you resigned and then gone later is NOT proof, since it could have been stolen by someone, but the employer is not liable for the criminal acts of other people, even other employees, since criminal acts, being against the law, are not something an employer is assumed to authorize, encourage, assist, etc. So since you don't appear to have evidence of what happened, it is unlikely you can hold anyone liable, though you can, of course, file an insurance claim if you maintained the relevant or appropriate insurance.