And in Sweden what in the US would be called a "juvenile detention center" would fall under the term of "youth home". He wasn't returned to the same one.
I don't think they're exactly leaving him unguarded, being underage, there isn't another type of facility suited for legally incarcerating him. These facilities essentially double as juvie and orphanages.
Mixing kids who are simply in government care with ones that are violent, was never a good idea though. These two systems should be separate, because it's now turning the former into the latter.
According to accounts for this story from eight sources including a former gang member, several youth home workers, prosecutors and criminologists, the homes have turned into recruiting grounds for gangs, who use them to enlist killers too young to be jailed.
Gangs have essentially found a loophole for legal murder. Get a child to do it.
They're the ones masterminding this shit. It's not like these actual children, with government rooves over their heads, are taking on contract killing to make ends meet.