A US computer science professor who played a key role in the creation of the internet search giant Google has been found dead at the age of 47 after apparently falling into his swimming pool.

Rajeev Motwani was mentor to Google's founders, Larry Page and Sergey Brin, when they were PhD students at Stanford university. His body was found in the pool of his home in Atherton, California, on Friday.

A spokesman for the university said the cause of death was unclear. Friends said he could not swim, but was planning to learn. Some reports speculated that Motwani, who regularly worked late into the night, could have accidentally fallen into the pool after going outside in the dark.