My dad took me to see a horror movie when I was a little girl (some time between 1964 and 1969) (probably too young for my own good) that made a deep impression on me but I never did remember the title of it. My dad died this year and I never thought to ask him and now it's too late. I'm hoping someone here can help me.

The movie starts out on a train with a police officer escorting a prisoner. During the trip, the prisoner finds a way to escape and jump off the train while it's crossing a bridge and falling into the water. In the process of freeing himself from the handcuffs, he loses his hand. The escaped man then has his stump fitted for a hook and has other attachments made to fit, as well.

He seeks revenge and butchers many people. Body parts of each victim are wrapped and mailed (to the police?). The authorities grow more and more desperate to find the killer.

That's all I can remember.

I don't watch horror films anymore but it was one of the things my dad spent time with me doing when I was a kid so it makes me nostalgic to remember those times now.

Your help will be appreciated.