Is She Really Gone?

"She is really gone. The love of my life... just taken away from me!"

Main character, Johnny just lost his wife, Mary Jo. The couple was deeply in love, until one day. Mary Jo suddenly died leaving Johnny all by himself with a broken heart and thinking that everything is hopeless.

Everyone tells him how it is weird that she just suddenly passed away with no explanation.

Did someone kill Mary Jo? Who would do such a thing to someone with such a kind heart?