The victim lived in a Cherry Creek apartment by herself from September 2014 until February.
She said she noticed underwear was missing - pricey thongs in particular.
She thought nothing of it, but then installed a camera and saw a man taking them.
The thong thief took about $1,200 worth of underwear and he has not been caught.
Anyone with information is asked to call Metro Denver Crime Stoppers 720-913-7867.