There were very few behaviors that were considered “criminal.” Murder is the most discussed crime in the historical record and in most cases the treatment of the murderer was decided by the victim’s family. They could avenge their relative’s death by executing the murderer or they could accept gifts to “cover their dead” (symbolically burying the diseased through expressions of genuine sorrow). In some cases the murderer was even adopted into his victim’s family to take the place of the dead relative.
Disputes and disagreements of less a serious nature were also handled by family groups unless they appealed to a civil leader to intervene and mediate. Most disputes were solved through gift giving, but sometimes other measures were taken. The most severe punishment a community could use was banishment from the community (for many this was worse than death).
The neenawihtoowa (war leader) served as a kind of village police, but this role was extremely limited as there were very few criminal behaviors. The best example of the work that a neenawihtoowa might do is stopping individuals or small groups from leaving a village and heading in a direction that might disrupt a herd of bison or some other large game for which the community was staging a large hunt. They often used fire to hunt bison (pre-gun), and for simple issues of safety and coordination community members needed to be reminded not to disrupt the group effort.