In Australia, organised crime has taken to hiring teenagers as hitmen; e.g. the perpetrators of a failed assassination attempt against a retired footballer (they shot him but he survived) included a 15 year old and 16 year old – https://www.smh.com.au/national/nsw/sixteen-heart-pumping-ab...
Reasons for using teenagers include that they cost less, they are impressionable, easier to manipulate, eager to "prove themselves", and receive more lenient sentencing (especially those under 18). Adult hitmen demand thousands, they'll find a teenager willing to do it for $500 (AUD 500 = USD 350). https://www.smh.com.au/national/nsw/at-the-crossroads-offend...
Apparently, this strategy wasn't invented in Australia, Australian criminals have copied it from Europe where it was already established (particularly in Sweden and the Netherlands)