Cat Mafia?

There is a grey cat in my garden as of late. This is the same grey cat that I threatened to capture and abandon 30miles away - I'll perhaps explain that one another day.
It's been taking advantage of my girls and their naivety, I often see him disappearing in my garage meowing and they just trot along after him. I really need to have that talk with them about the "bad boys" of the feline world, and "just say no".
Now my boy cat has put up with this for only so long, every night he has been demanding to go out at 5pm just so her can go "rumble" with this cat. I have no idea why though since I always find him yowling, submissive and crouched under something while being beaten up, and last night was no different.
I came down the stairs to hear a massive cat fight outside, I threw the front door open and mr grey had pinned my darling Roarke to the ground underneath a car. I strode out...(in a see-through nightie no less) umbrella in hand and attempted to beat mr.grey off-of my property.
He left, more because he decided to, than because I actually achieved anything, and poor Roarkle came in acting like it was all a fuss over nothing when I could clearly see he'd literally wet himself.

This morning all three cats were anxious to get out of the front door, we opened it and there on the doorstep was a dead mouse. All three cats immediately adopted a crouched "ears back" stance, as if they had just been gifted a dead horse head, and refused to step outside.
Now I don't know exactly what the dead mouse means, whether it is an offering of love (yeah right, why buy the cow when you get the milk for free) or ...given the reaction...a promise of death. Cat Mafia maybe? I wonder where we humans fit into their payback plans. Can cats start fires? Maybe I'll just go test the smoke alarms....or maybe we really need a puppy now.

UPDATE: On further inspection the dead mouse's head has been cleaved in two.....