Li said the men had documented excessive overtime, with working days sometimes stretching longer than 18 hours, and a base salary below minimum wage. They were working to confirm evidence suggesting that student interns — some of whom allegedly quit in protest — were putting in excessive hours on work unrelated to their field of study, in violation of Chinese law, Li said. The use of student workers in China is legal, but meant to be strictly regulated. Rights groups and journalists have documented widespread abuse of the system over the years.