Human brains stored in jars of formaldehyde at the University of Texas in Austin and reported to be missing were actually destroyed in 2002, school officials said on Wednesday.
Environmental workers disposed of the specimens after faculty members determined they were in poor condition for use in research or as a teaching tool when they were received in the 1980s, the university said.
"We believe the workers disposed of between 40 and 60 jars, some of which contained multiple human brains, and worked with a biological waste contractor to do so safely," the university said in a statement.
One of the missing brains was believed to be that of Charles Whitman, a former Marine who killed 16 people and wounded dozens in a campus shooting spree in 1966, but the university said it had no evidence linking the specimens to Whitman.
The university received about 200 brain specimens from the Austin State Hospital in the 1980s, a mental health institution, and currently has about 100 in its collection, university spokesman Gary Susswein said.
The university is investigating the decision to dispose of some specimens and is looking into how all of its brain specimens have been handled, it said.