When a grieving teacher is blackmailed over the death of his brother, he decides to silence the blackmailer and frame his widow’s new lover for the murder.

I like this. It starts strong. It ends strong. There's a lot of intrigue here, and as I reread it, I can't help but be slightly confused. What drives a character to escalate so quickly from being blackmailed to murdering and framing the murder on someone else? I wonder if you could tie the characters closer together in the story.

Sounds to me, like the guy is a reformed hitman of sorts who (reluctantly?) returns to his old ways. Also seems like it's a win-win situation for him. Can you tell us what the risk is? Other than being found out, perhaps.

An odd reaction. Is there a reason he doesn't go to the police?