One Tree Hill actress Sophia Bush has petitioned to annul her five-month marriage to Chad Michael Murray, PEOPLE has learned.

In papers released by the Los Angeles Superior Court, the actress cited “fraud” as the grounds for annulling the union. There was no explanation of the alleged fraud.

A fraud claim can be “difficult to prove,” Hollywood divorce attorney Sorrell Trope told PEOPLE. If a judge denies Bush’s annulment request, she can seek a divorce from Murray.