Amnesty International allegespolice beat protesters, tortured detainees and at times took part in riots with Hindu mobs. The Amnesty report says that while Hindus also suffered losses, Muslims were disproportionately targeted in the riots.
"The riot that seemed far from spontaneous saw almost three times the number of Muslim casualties compared to Hindus. Muslims also bore the brunt of loss of business and property," it said.
The Citizenship Amendment Act (CAA) - which critics say is anti-Muslim - sparked massive protests across India after it was passed last year. One such demonstration in Delhi turned violent - clashes broke out between protesters for and against the law. The violence soon took religious overtones and the rioting continued for three days, with Muslim homes and shops being targeted by violent mobs. The report says its forensic analysis of videos from the rioting supports the conclusion that the police stood by, allowing rioters to wreak havoc in some places.
It also alleges that hate speeches by right-wing leaders sparked the riots - but notes that the police have taken no action against them. On the other hand, it says, police have arrested civil rights activists, teachers and students, most of them Muslim.
"Not even a single political leader that made hate speeches, which advocated violence in the build-up to the riots has been prosecuted," it said.
"As the Delhi police investigate who is responsible for the riots, there have been no investigations till now into the human rights violations committed by the Delhi police during the riots," says the report.