A series of online attacks on Google and dozens of other American corporations have been traced to computers at two educational institutions in China, including one with close ties to the Chinese military, say people involved in the investigation.

The Chinese schools involved are Shanghai Jiaotong University and the Lanxiang Vocational School, according to several people with knowledge of the investigation who asked for anonymity because they were not authorized to discuss the inquiry.

Jiaotong has one of China’s top computer science programs. Just a few weeks ago its students won an international computer programming competition organized by I.B.M. — the “Battle of the Brains” — beating out Stanford and other top-flight universities.

Lanxiang, in east China’s Shandong Province, is a huge vocational school that was established with military support and trains some computer scientists for the military. The school’s computer network is operated by a company with close ties to Baidu, the dominant search engine in China and a competitor of Google.

“We have to understand that they have a different model for computer network exploit operations,” said James C. Mulvenon, a Chinese military specialist and a director at the Center for Intelligence Research and Analysis in Washington. Rather than tightly compartmentalizing online espionage within agencies as the United States does, he said, the Chinese government often involves volunteer “patriotic hackers” to support its policies.