This really happened to me, about two years ago, when I was living in the house on Catalina Drive, Phoenix.
This will take a little explanation: in that house the kitchen/dining-room area is cut off from the hallway not by a complete wall but by a waist-high counter that runs back to a doorway near the back kitchen wall. Anyone standing in the hallway could be seen over the counter by anyone at the front door or in the kitchen/dining-room. Anyone lying on the floor couldn't be. Got that? Okay.
I was busy with my email when I heard a howling, thumping disturbance out in the main part of the house. I got up and went out and saw, in the hallway, a strange woman fighting with one of my tenants. The woman had a knife and was hacking at the tenant, who had grabbed her from behind and was squirming to avoid the knife.
So I pulled out my gun (the little-bitty North American Arms .22 mini-revolver, so small you can cover it with one hand), pointed it at the woman and yelled: "Freeze!"
Probably because we were in a working-class neighborhood, where people have experience with such things, the woman promptly froze -- and then dropped to the floor. The tenant grabbed the knife out of her hand and got out of the way fast, setting the knife on the counter as she passed. The woman on the floor began to cry, but had the sense not to move. I kept my gun pointed at her and told the tenant to call the cops, which she did.
At that point the action stopped. Then tenant sat down in the kitchen and waited. The woman on the floor cried and waited. I "held the point" (i.e., kept my gun aimed at her) and waited. We all waited for the cops to show up, and it took them a good quarter-hour or a little over. Since I was holding the point with my arms fully extended, you can imagine that they began to get tired. I leaned against the nearest wall to brace my arms, but it didn't help much.
*Finally* the cops came to the front door and knocked, and the tenant hurried to let them in. They stopped at the door, looked around, saw me standing sideways to them aiming my gun at something they couldn't see down the hallway, and they said what cops always say when they see any armed civilian: "Police! Freeze! Drop your weapon!"
I wasn't about to let the woman have a chance to escape, so, *carefully not looking at the cops*, I replied: "Police, help! Come put your guns on this perp so I can take mine off."
The cops looked at each other as if they'd never heard of such a thing, tippy-toed a little closer, and shouted again: "Police! Freeze! Drop-your-weapon!"
Again, keeping my eyes on the woman, I called back: "Police, help! Come take charge of this perp."
Again, the cops exchanged glances and tippy-toed a little closer. Again, they gave their standard call, and again I answered. Step by step, "Police! Freeze!" by "Police, help!", they made their way close enough to the counter to look over it and see that, yes, I was holding my gun on a woman who was lying on the floor crying.
Finally one of them had the sense to come around the end of the counter and say: "It's all right, we've got her." I said: "Finally!", pulled up my gun (pointing it safely at the ceiling), and started to shove it back in its belt-holster.
"No-no-no!" snapped one of the other cops. "Don't put it away; give it to us."
What the hell, it was a cheap little thing; if the cops elected to steal it (which they usually do with citizens' guns), I could replace it easily, so I handed it toward the nearer cop. He jumped back, wailing: "No, don't point it at *me*!" -- though in fact, I wasn't. I dutifully pointed the muzzle back toward the ceiling and handed it toward him again, and this time he took it -- with such exaggerated care that you'd think I was handing him a grenade. He carried it away, fussing with it. I started rubbing my cramped arms and grumbling about having to hold the point for a good 15 minutes while I'd waited for them to show up.
While the first cop cuffed the woman (which seems to be another of their standard behaviors), I explained to a third cop what I'd heard, seen and done. I also showed him the knife -- which he looked at, pronounced "a cheap Chinese job", and then ignored.
As the first cop was frog-marching the woman outside, and the third was questioning the tenant, the second came up to me and shamefacedly asked me how to unload my gun. After an instant's astonishment, I told him. He still couldn't do it. I offered to unload the gun for him, but oh no, he wouldn't let me touch it again until it *was* unloaded. *Sigh* Impasse. Finally, I set my hands over his and showed him: "Take the knurled end of the rod under the barrel between your thumb and middle finger, then press the end of the rod firmly with your index finger, then pull the rod out. Now pull the hammer very slightly back, and push the cylinder out of the frame." It took three tries before he got it. The gun was now in three harmless pieces -- frame, cylinder and rod -- and he didn't seem to know what to do with it. I gave up on the whole business, went back into the computer room and resumed working on my email.
It took half an hour to straighten the whole mess out. The tenant chose not to press charges, the woman left her knife right where it was and departed, and the cops went back to their cars to make reports. One of them came up to me and handed back the pieces of my gun, and they all went away.
What did I conclude from all this? First, that the cops do *not* show up quickly, even when you tell them there are "weapons" involved. Second, even in a no-gun-control state like Arizona, the cops assume that any civilian with a gun is automatically the Bad Guy. Third, they don't seem to know what to do when the civilian has caught the Bad Guy and is holding him/her for them. Fourth, they're not as familiar with guns as they like to think. Fifth, that they won't steal any civilian's weapon if it's too cheap, too small or too complex for them.
The moral of the story is: if you catch a Bad Guy on your own hook, make sure you do it with a cheap and/or complex weapon that the cops won't want. Also, if you hold the perp for the cops, be sure to have a friend standing near who can explain -- fast and loudly -- that the person holding the weapon is the Good Guy. And of course don't point either the weapon or your eyes at the cops. It also helps to memorize the words: "Police, help! *He's* the perp; I'm the Good Guy!" -- because they certainly can't tell from looking.