[Dajjal]

If Mr. Young was bumped off because he knew to much, why wasn't Larry Sinclair rubbed out, since he knew the same story?

Supposedly because the killer had easy access to Young through the Trinity church, and easier ways to get away with it through Chicago corruption.

[ANGGAPO]

Ok, but in Chicago it would be easy to get the job done on both of them. Letting a loose cannon like Sinclair still around running his mouth off is sure to light a fire someplace.