Nefertiti is believed to have been Tutankhamun's stepmother. Nicholas Reeves, the Egyptologist in charge of the investigation, theorizes that the tomb was actually built for her, but since Tutankhamun died young, he was buried in an outer chamber of her tomb because his was not completed.

There are several reasons why the investigation has only recently yielded even tentative results. First, some archaeologists believe Nefertiti's remains were already discovered at a different site long ago, or that even if they weren't, that she is more likely to have been buried elsewhere. Also, the technology to perform high-resolution scans and other forms of non-invasive digital imaging is very new. These sites are priceless spaces of historical, religious, and national meaning and memory - it's very hard to get the necessary permissions to investigate them. IIRC, Reeves had to wait something like 3 months for permission to use the radar machine so that they could make sure it wouldn't damage the walls.