Ten people, including teenagers, were killed in Indonesia's post-election riots in May this year, the human rights commission said as it accused police of beating up protesters.
In its final report on the riots, the Komnas HAM agency said on Tuesday that four of the victims were minors and most were shot in the capital Jakarta and demonstrations in Kalimantan, Indonesia's section of Borneo island.
The rights commission called on police to find the perpetrators, who it suspected were "actors trained, organised and professional in using guns". It did not elaborate.
"This is a tragedy," commissioner Beka Ulung Hapsara told AFP news agency.
"These are unlawful killings - or killings that took place outside legal mechanisms - and that violates the criminal code," he added.
The commission said it did not suspect authorities were behind the shootings. But it accused police of using unnecessary force against protesters, including minors.
The police used violence against children who joined the rally [in Jakarta] during which they said that they were beaten and kicked when arrested, according to the report.
A Jakarta police spokesman declined to comment, saying that authorities had yet to see the agency's report.
Supporters of losing presidential candidate Prabowo Subianto took to the streets after Indonesia's Joko Widodo won re-election in the world's third-biggest democracy.
Police detained some 465 people during two nights of street battles that paralysed central Jakarta, leaving hundreds injured, the rights agency said.
Also on Tuesday, police on the island of Sulawesi said a half dozen officers had been slapped with three-week suspensions for bringing guns to protests last month in Kendari city, where two students died.
"They [the officers] were found guilty of not following orders by bringing firearms" to the rally, said Southeast Sulawesi police spokesman Harry Goldenhardt.
The force did not accuse officers of killing the students.
The pair died amid nationwide protests against a host of divisive legal reforms, including banning pre-marital sex and weakening the anti-graft agency.
Hundreds were injured in the demonstrations with police also accused of brutality against protesters.