DENVER (AP) — The University of Colorado, Denver confirms it received a suspicious package on campus that it turned over to authorities.

In a statement Wednesday, the university wouldn’t confirm the package’s contents or the sender.

Multiple news outlets have reported that the former neuroscience graduate student accused of killing 12 people in a Colorado movie theater sent a notebook to the university containing scribblings of stick figures being shot.

The university said Wednesday that the package was immediately investigated and turned over to authorities within hours of its delivery Monday.

Citing unnamed law enforcement sources, Fox News’ website reported that James Holmes sent the notebook in a package that had sat unopened since July 12.

In the statement, the university disputed that it received the package on July 12 but did not elaborate.