There is no cut and dried answer to whether your employer can search your personal property. As a general rule, however, if an employer informs his employees that they are subject to personal searches, and they comply as a condition of employment, the employer can search your personal property.
Having a clear and specific search policy can usually grant your employer the right to search your personal belongings. He should have good cause and you should have no reasonable expectation of privacy in the item searched. For example, an employer can search your personal belongings if he has a search policy in place that lets him search company-owned lockers for suspected weapons. If you refuse to consent to the search, you could be terminated. Purses and briefcases are generally considered off-limits and searchable only with your permission or with a court-ordered warrant.
Circumstances regarding personal property searches in the workplace can get legally complicated. For example, if your purse is in your locker, and your employer searches your purse, a court could rule that you had no expectation of privacy, but it could also rule the search unreasonable. It's best to seek legal advice from an attorney to determine if your employer was wrong and whether you should take action. Some landmark court decisions have reinforced the importance of having a search policy. In "K-Mart Corp. v. Trotti," an employee sued her employer, citing a violation of privacy, when the employer searched her locker. She won the suit in part because the employer had no search policy in place.