Starter will not disengage

I need some help. My starter was starting to go bad so today I took it off and bought a new one at Autonzone. Immediately when I tried it, the starter would crank turn on the engine and would not disengage until about 20-30 seconds later. My brother works at Autozone and was helping me out so he probably told me that it was a defective starter (i bought the remanufactured one). We returned it and got it swapped out and upgraded to a completely new starter. Put on the new starter and still did the same thing. This time it seems like the starter didnt want to disengage. After 30 seconds I shut it off because I was afraid to burn it out. My next thought was the ignition switch, so I changed that out as well and no luck. I've checked the fuses and they all seem to be ok.
does anyone have any ideas what it could be?

Thanks!

if the little wire is holding power after you let off, its your car, but my money is on.....
Junk starter, hate to burst bubbles, but autozone is not the best parts house. Go to carquest or something the pros use and get it. Autozones saving grace is shade trees and the fact that nothing else is open at 900 at night. I won't use em for anything other than oil and fluid stuff.

Well I thought it was the starter at first so that's why I replaced it with a brand new one (according to AZ its a new one and not a reman). So the same thing happening to both starters is a little wierd. I would have to say its the car but I'm a little lost on what to check next. Possibly the cylinder???

Ok, update!
I removed the ground wire from the starter and viola, no problem when it started. I tried it like 10 times just to make sure and the starter disengage correctly every single time.
Now another problem.
Battery light popped up on the dash. Disconnected the battery with the car on and it shut off. I took out the alternator and got it tested at AZ and Oreilly's and they both said it was good. I put the alternator back on and turned on the car and no battery light until like 5 minutes later. I think I'm just gonna buy the alternator and hopefully that fixes the problem. Thanks for your help everyone.

Update: Bought new alternator and still same problem.
I have noticed that when I connect the ground wire to the starter like it should be, when I start the car the starter keeps spinning and doesnt disengage but also the battery light will not pop up on the dash. when the car starts normally and the starter disengages correctly the light pops up. Could it be the Ignition cylinder, being that I already replaced the ignition switch.

Thanks

This reminds me of a similar problem I had with a 1986 Toyota. The starter would keep on cranking even if I turned the ignition off. The only way to stop it was to disconnect the battery.

I removed the starter and opened it and found that the connection between 2 field windings was touching the starter housing. I had the starter circuit at hand but could never figure out exactly what was taking place and why the short circuit would do this. After wrapping some insulation tape around the wire the starter worked fine.

Now I'm not suggesting that your problem is the same seeing as you have tried 2 starters but who knows? This might also account for the behavior of the alternator light.

It's been some time but I figured out the problem. I looked at the schematics and realized that i STUPIDLY put the wire coming from the alternator on the ground of the starter. Duh! no wonder the starter wouldnt shut off, it was getting power from the alternator when the car was on. and duh the battery wasnt charging because all the power was going to the starter. I feel like an idiot. But oh well I learned.

Thanks to everyone for their help.