The girlfriend of a 24-year-old man charged with stabbing a police officer was among seven Hongkongers arrested on suspicion of helping him try to flee the city.
Senior Superintendent Yau Kin Hung said the group of five men and two women, aged between 24 and 71, had been picked up by officers in a series of raids on Thursday.
According to Yau, the seven were suspected of providing varying degrees of help, including buying a plane ticket for Wong Kwan Wa, and taking him to the airport.
Police also believe the group gave Wong information about the investigation, Yau said.
In Hong Kong, assisting offenders carries a maximum penalty of 10 years in jail.
The senior superintendent said the investigation was under way and further arrests were possible.
As of 12pm on Friday, the seven suspects were still being held for questioning and none had been charged.
The attack occurred outside Victoria Park in Causeway Bay at about 4pm on July 1, when an officer was stabbed during a protest against the national security law.