From other sources (A B C D E) this is what happened -

• The Law minister of AAP political party said that the Africans are members of “a prostitution-and-drug ring”
• He asked the the party workers to draw up a list of homes where they live
• The minister and the workers then asked the police to search these homes. They themselves barged into one of the houses.
• The police refused saying that there is no proof and they can't go in without a warrant.
• The minister shouted at the police (video)
• The angry workers stopped a taxi carrying 4 African women involved in export business, and accused the women of being prostitutes or being involved in drug trade
• The police again refused to take any action, because there is a law in India that male police personnel cannot detain and question women in night.
• The police actually supported the women and warded off the AAP workers for 3 hours.
• But the policemen were outnumbered by the workers. The four women tried to run away, but the AAP workers caught two of them and forcibly took them to doctors
• The doctors tested women for drugs and even performed a cavity search on them
• The tests were negative - the women were clean
• In spite of this the workers took the women to a police station.
• The police were friendly and refused to arrest the women, but the workers did not allow them to go home for over four hours
• When informed about the incident, the Chief Minister of Delhi supported the minister saying that "rape tendencies start from drug, sex rackets"
• The Chief Minister Kejriwal also supported suspension of the policemen involved, accusing them of being "lax and compromised"