How Are High-Profile Violent Offenders Treated in Prison?

Not well by other inmates, and likely in protective isolation by the administration.

Prison has its own moral hierarchy, and at the bottom of it sit people whose crimes targeted children and the vulnerable. Someone convicted of deliberately killing and injuring innocent people, including children at a community event would be marked from the moment their case became public. News travels fast inside, and other inmates would know exactly who they were dealing with.

The facility would almost certainly not place this person in general population, at least not without significant protective measures. The risk of violence from other inmates would be assessed as high, and the administration has an obligation to maintain safety even for the most reviled inmates. In practice, that usually means administrative segregation, protective custody, or a housing unit for high-profile or at-risk individuals separated from the general population.

Even in protective custody, the social reality of being known as someone who targeted children at a community celebration is brutal. Prison culture does not offer rehabilitation of reputation. The label follows permanently.

High-profile cases also generate ongoing attention from both inside and outside the facility. That kind of notoriety creates its own set of complications for the administration and for the individual's daily existence.