Valley investor and Google adviser Rajeev Motwani mourned

This post was updated on Monday, June 8, with Motwani's correct age, as well as the cause of death and names of surviving family members.

Condolences are pouring out over the Internet as news spreads that Rajeev Motwani, a Stanford University computer science professor and well-known Silicon Valley angel investor, was found dead in his backyard swimming pool Friday. He was 47.

Motwani, who friends say did not know how to swim, was a special adviser to Sequoia Capital and invested in companies including PayPal and Google. But he may have been best known for mentoring numerous Stanford graduate students, including Google co-founders Larry Page and Sergey Brin.

"Officially, Rajeev was not my adviser, and yet he played just as big a role in my research, education, and professional development," Brin wrote on his blog Friday. "In addition to being a brilliant computer scientist, Rajeev was a very kind and amicable person, and his door was always open. No matter what was going on with my life or work, I could always stop by his office for an interesting conversation and a friendly smile."

Motwani, a native of New Delhi, India, received his Ph.D. in computer science from the University of California at Berkeley in 1988. His research spanned a diverse set of areas in computer science, including databases, data mining, and data privacy; Web search and information retrieval; robotics; computational drug design; and theoretical computer science.

He authored two books--"Randomized Algorithms," and an undergraduate textbook published by in 2001. Among other honors, he won the prestigious 2001 Godel Prize, which is awarded for excellence in the field of theoretical computer science.

Wrote Brin: "Today, whenever you use a piece of technology, there is a good chance a little bit of Rajeev Motwani is behind it."

Motwani sat on the boards or advisory boards of Google, Mimosa Systems, Neopath Networks, Revenue Science, Stanford Student Enterprises Ventures, and Vuclipa, among others. He was also active in the Business Association of Stanford Engineering Students.

His success, however, "never came in the way of Rajeev's quest for knowledge and innate desire to help others," wrote blogger Om Malik, a friend of Motwani. "There wasn't a start-up he didn't love."

Silicon Valley angel investor Ron Conway pays further tribute to Motwani in the video below, saying, "He shared my attitude that the more entrepreneurs you can help, even if you only give them five minutes, go do it. He never refused a meeting with an entrepreneur that I suggested he meet just to give them some quick advice."

Motwani is survived by wife Asha Jadeja, and daughters Naitri and Anya. We're not aware of details on funeral arrangements yet but will update this post as soon as we hear.