Dr Chris Parr, a professor in religious studies at Webster University in St Louis, was arrested last week, local news website KMOV.com reported.
His arrest on Wednesday night came on the same night two police officers were shot and injured during a protest outside the Ferguson police station.
The protests began after fatal shooting of Michael Brown, 18-year-old black man, by police in August last year.
Unrest was reignited by a Department of Justice report released earlier this month, which showed a pattern of discrimination against the black population.
KMOV.com reported Dr Parr as saying he believed police needed to talk to the people to find out why they were so upset.
Officers needed to "admit they have done a bad job, as the Department of Justice has said, and make things different," he said.
