Police used “unnecessary and excessive force” in making arrests, beat a protester for declining to answer a question and then pinned him to the floor, shined laser pens in the eyes of people who had been detained, and threatened to electrocute a man’s genitals after he refused to unlock his phone, the human rights group said.

Amnesty said it released its findings after an investigation that included interviews with 21 arrested protesters, corroborating interviews with health care workers who treated demonstrators, and lawyers representing people who had been detained. Out of 21 protesters interviewed, 18 were hospitalized for injuries or illnesses related to their arrest and detention, the group said, adding that it also reviewed medical records.

The Hong Kong Police said it would not comment on individual cases. In a statement released to Bloomberg News, it said police officers would give warning of their intention to use force when circumstances allowed. Officers are required to use a “high level of restraint at all times,” it said.

The rights group said it shared its findings with the Hong Kong Commissioner of Police on Sept. 18, but had not yet received a response. Contacted on Thursday, police didn’t have an immediate comment.

The group, which also shared its research with several members of the city’s Legislative Council, said it was publicizing its findings anyway given the “gravity of the abuses,” escalating violence on both sides and the possibility the “situation could deteriorate further in the coming weeks” ahead of protests planned to coincide with the Oct. 1 anniversary of 70 years of Communist rule in China.