Are there ways to tell if our mate's other half's knocking the **** out of her again?

(Apart from the obvious, of course), and, if so, what are they, please? Only, one of mine and my girlfriend's mutual friends' live-in boyfriends beat her up quite bloody badly a few years back- (the !), and, of course, the git cried his eyes out, (spare me!), told her how sorry he was, that it was "really out of character" for HIM, that it "wasn't him", and that he "promised and swore on his life that it'd NEVER happen again" (!) Ya know?! All the usual crap you'd expect to hear from the bloody likes of a piece of **** like him! Anyway, our mate fell for this bullshit hook, line and bloody sinker- (not us, though!) We've both been really worried about her ever since we found out- (me, especially!) Are there any ways in which we can tell if the bugger's still knocking her about, (other than, as I said before, the obvious), and without her actually outright saying: "He's hit me again"? Only, like I said before, we are both quite worried about her, and she ain't likely to say "He's hit me again", to me again, because she knows I'll go mad if she does! So, what are the other ways of telling if he's been knocking her about again, please? (Apart from, like I said before, her telling us, and cuts, bruises and whatnot, which, let's face it, probably wouldn't be where anyone could see them!) I'd really appreciate your angles on this one, please, guys. Much obliged! Peace and love! Be lucky! :)