In 2007, neuropathologists from the Sports Legacy Institute (an organization co-founded by Christopher Nowinski, himself a former professional wrestler) examined the brain of Chris Benoit, a professional wrestler with WWE, who killed his wife and son before committing suicide. The suicide and double murder were originally attributed to anabolic steroid abuse, but a brain biopsy confirmed pathognomonic CTE tissue changes: large aggregations of tau protein as manifested by neurofibrillary tangles and neuropil threads, which cause neurodegeneration.