How did thieves reset my Apple ID password and deactivate Find My iPhone

I recently lost my iphone or it was stolen quickly while I left it on the table. I don't remember if the the screen was locked when the thief took it, but 15 minutes after I checked my email I found two concurrent emails from Apple:

1) Your Apple ID password has been reset.

2) Find My iPhone has been disabled on XXX.

In what scenarios would the above have happened? Would the thief have been able to achieve this within (15) minutes of taking my phone only if the screen was unlocked?