Manhattan —

Tammy Tozer completed her week-long quest to find the owner of an SD card – filled with 1,800 photos snapped around the world – that she found at the 9/11 memorial.

After she posted two of the pictures on Facebook, users helped her track down the card’s owner, Georg Witt, a German singer who was in the city performing with the Radio Chorus of Berlin.

Although Witt’s story has a happy ending, Tozer is still looking for hers: She is desperately seeking a kidney transplant match. None of her friends or family are matches. Doctors tell her she needs a donor with a rare O-negative blood type.

Interested donors should contact the Kidney Transplant Treatment Team at the University of Pennsylvania.