Pepper spray university UC Davis 'hid search results'
The university at the centre of a pepper spray row paid consultants more than $175,000 (£123,000) to bury online search results about the incident.
In 2011, a police officer pepper-sprayed students protesting at UC Davis, California, at close range.
The university later hired consultants to "eradicate references" to the incident in search results.
UC Davis said it wanted the reputation of the university to be "fairly portrayed".
Videos of the incident, which have been viewed millions of times online, show a police officer pepper-spraying students who were peacefully protesting on the university campus.
In a statement issued at the time, university Chancellor Linda Katehi said she was "deeply saddened" by the event and took "full responsibility for the incident" but refused to resign when challenged by the university's academic staff association.
"I do not think that I have violated the policies of the institution," she said.
Documents released after an investigation by local newspaper the Sacramento Bee found that the university hired consultancy Nevins & Associates in 2013 to "eliminate" Google search results.
The consultants identified "online evidence" and "venomous rhetoric about UC Davis" was being shared online.
The campaign was also designed to eliminate negative search results about Dr Katehi.
Documents suggested this could be achieved with a "flood of content with positive sentiment and off-topic subject matter", and proposed hosting content on Google's own services, which would appear higher in the firm's search results.
Speaking to the Sacramento Bee, UC Davis spokeswoman Dana Topousis said: "We have worked to ensure that the reputation of the university, which the chancellor leads, is fairly portrayed."
The consultancy was paid by the university's communications department. Its budget has increased from almost $3m in 2009, to $5.5m in 2015.