Egyptian officials now say they are "90% sure" that there is a hidden chamber in King Tutankhamun's tomb.
The Antiquities Ministry said it had carried out scans to gather more information about the theory.
Archaeologist Nicholas Reeves believes Tutankhamun's remains may have been rushed into an outer chamber of what was originally Queen Nefertiti's tomb.
The remains of Tutankhamun, who may have been her son, were found in 1922. He died 3,000 years ago aged 19.
"Clearly it does look from the radar evidence as if the tomb continues, as I have predicted," Mr Reeves said at a press conference with the Egyptian Antiquities Minister Mamdouh al-Damati on Saturday, AFP reports.