How did Richie know?
When Matthew Bevilacqua (Drinkwater) and his homie Sean Gismonte shot Christopher, and Matty went running to Richie for protection he was out of breath and wearing the same clothes, so I imagine he ran immediately to Richie's after the shooting and not much time had passed.
When he barged in and asked Richie if he knew what happened to Christopher, Richie said he'd heard already.
I know that obviously telephones existed in that day and age, but realistically how the hell did Ritchie find out so quickly? He's hardly close to Christopher, and he's not his captain or relative. I'd imagine in the chaos of phone calls that likely began once word of the shooting made it's way to the Soprano Family, Richie would be pretty far down the list of people to inform.
So how the hell did he find out all about it before Matthew made it to his social club? That question always bothered me a bit whenever I saw that scene.