His record is all of molesting males, correct.
However, many many molestation cases end up with the victim murdered. Men who prey on young girls...several cases in the news...kidnap, molest and murder them. Likewise, men who prey on young boys often murder them. John Wayne Gacy comes to mind, Jeffrey Dahmer, surely there are many others. Lots of young boys have disappeared, never to be found, or their remains found months or years later. Many cases are never solved, but the victims are presumed lost in the prostitution-porno realm, or dead.
One liklihood is if the boy resisted the pervert, that could have ended up in his death. Or it could be just from the mind of the sicko, that he planned to kill him no matter what.
That makes sense. But I still wonder why he didn't kill Shasta. Obviously, keeping her alive was a liability for him.