things tend to be relative, hence statistics are a thing. The gun murder capital of Europe without some hard data as to what that means sounds a bit like the radiation poisoning center of Antarctica, gang members as young as 14 can definitely be increasingly doing things if before they started increasing there were zero gang members below 14 using explosives etc.
Another problem is just taking what the police say as being "true", for example the police say there are 62000 people in Stockholm (a city of slightly over 920000) "linked" to criminal gangs - https://www.reuters.com/world/europe/sweden-has-around-62000... this article uses the word linked twice, in the title linked to criminal gangs, and later in the article "the authorities have struggled for years to contain violence linked to organised crime." I wonder if they have 62000 people who are violent in their linkage, somehow I doubt it but this seems to be the impression.
Hey, I bet there is a problem, how big of a problem, probably not as big as these news stories imply. Why not? Well because if I had a really big nasty problem I wouldn't just imply it, I would lay it out, plenty of engagement to go around, but if my engagement could benefit from exaggerating the problem then I will imply instead of stating plainly.
At any rate more than 6% of the population of Stockholm is currently not involved in a violent gang war which one might infer from the reportage.