The University of Minnesota filed a lawsuit Monday alleging violation of copyright law against a website operator who had posted the psychological test it developed online, according to Minnesota Public Radio News.

The MMPI test has been widely used in the past two decades to diagnose mental disorders, MPR reported. It has more than 500 questions.

Andrew Dobson of New Zealand allegedly posted the test questions and the software to interpret them on two websites. MPR said both websites removed the content following a letter threatening legal action.

The test must remain private, University attorney Stuart Hemphill told MPR, because if test takers have seen the questions beforehand, it throws the validity of responses into question.

The lawsuit, filed in conjunction with testing company NCS Pearson, Inc., will likely be withdrawn if the websites cooperate, Hemphill said.