Someone logging onto the Google Trends website at around 9 AM would have seen the phrase "lol n------". Many of the other terms were also unusually broad and not in keeping with the usual sorts of hot topic terms which appear on the page.
A spokeswoman said the company was "investigating reports of an unusual query appearing on Google Trends this morning" but had no further comment.
This would not be the first time a hacker manipulated the rankings, which went live in 2006. In in 2008, a swastika appeared as the top term. A week later, some wrote "f--- you google" in reverse.