It could be that the boys somehow provoked the butcher or got in his way. Or perhaps there's a deeper, darker backstory to the butcher's actions that hasn't been fully revealed yet.
The butcher in the comics kills the boys in a brutal manner. He takes advantage of their vulnerabilities and employs various weapons and strategies to ensure their demise.
Ezekiel's death in the comics was the result of a series of unfortunate events and encounters with powerful adversaries. It was a moment that shocked many fans.