Washington, July 17 - US police have concluded that the death of Rajeev Motwani, India-born Stanford professor and the mentor and adviser of founders of top internet firms like Google and PayPal, was a case of accidental drowning.

Police concluded their investigations into the case after the autopsy report released by the San Mateo county coroner's office revealed that Motwani's blood alcohol level was 0.26 when he died as against the US permissible driving level of 0.08.

San Mateo County Coroner Robert Foucrault termed it as an 'unfortunate accident'.

'It is difficult to know what effect a given alcohol level will have on a person because tolerance varies from individual to individual,' Foucrault said.