What is a "no-weapon kill?"

I've been trying to clear out the Saints Book, and I was working on Angel's "No-Weapon Kill" challenge.

I assumed this was simple, and I'd go up to cops/gangs and punch the crap out of them for a bit and get it. But, as this album attests to, I beat up the cops for a while. When I checked my progress on the challenge, though, I was still at 14/25 kills.

Clearly, at some point through playing the game, I've gotten 14 kills the game considers "no-weapon" kills, but I have no idea what I would have done to get them to count. I would have thought at least the wrestling moves would count, since that's what Angel would have wanted, but I made absolutely no progress towards the challenge.

What the heck does the game mean by a "no-weapon kill?"

No-weapon kills are just as you say - they're kills you make only with your fists. Any other melee weapon or gun will disqualify you. You can feel free to do wrestling moves, but I'd avoid the "nut assault" move, as I think that puts you in a different category of kill. Some of the melee moves also cause you to draw your weapons, even if you didn't intend to, so watch out for that.

I believe though, that you will have to do this against rival gang members. Several of these challenges distinguish between rival gang members and everyone else, even though they don't say so specifically.

Some of these moves will pop a little "respect circle" in the upper right corner of the HUD. I didn't see one for no-weapon kills on either gang members or police officers just now, so I'd just go kill a gang member with your fists and verify that the count is going up. You'll also see a "challenge progress" popup every so often, so keep an eye out for that. I think getting to 15 should make it show up.

I used to be confused by the requirements for this challenge until I found that only gang members count. Also, knock down kills conflicts with no-weapon kills (and don't count as the latter).