The Mean Girls star is currently serving a house arrest sentence after her conviction for shoplifting a necklace and she is not allowed to leave her home.
The authorities dropped by unannounced and found the actress watching TV and reading scripts.
It is unclear why the ankle device went off, according to the Los Angeles Times.
Steve Honig, a spokesman for the actress, says, “They (officials) came as part of standard procedure to make sure the monitoring equipment was working properly.”
The actress was sentenced to serve 120 days behind bars last month (May11), but jail overcrowding issues and the fact she is a non-violent convict prompted officials to allow her to serve a reduced sentence at home.