"Searches were carried out on 17 June to intercept and detain individuals who were involved on 4 May in a feud in Paços de Arcos, where there were robberies and assaults," said the PSP's operational commander in statements to reporters at the scene.
According to Ana Néri, the 12 young people are suspected of involvement in an occurrence, where there were thefts and assaults on Uber Eats couriers.
During the operation in which arrest warrants and house searches were carried out, the PSP also seized "clothing" that allegedly was used by the youth, drugs, pepper spray and a brass knuckle."
In a statement, the PSP said that the "large-scale" operation aimed to comply with search and arrest warrants for crimes of theft, offenses against qualified physical integrity and participation in a feud.
The detainees will be brought to court on Thursday, 18 June.