According to the Spectator:

Crone said that Sohn had been "noticeably upset," but had not physically resisted the police in any way. "He wasn’t attacking the officers or [doing] anything apparently violent against them," Crone said.

Another observer—George Cen, SEAS ’08,—said that while the police were questioning Sohn, two white students walked by carrying 40s. The officers instructed the students to cover their drinks with brown paper bags, but did not detain them...

... As the incident progressed, a crowd gathered and the officers called for backup, witnesses said. Three more police cars arrived. According to Crone, one of the officers said to the crowd—composed mostly of Asian students—"Have you had too much sake tonight?"

Read more about it here.

This will not be left undiscussed.