Antiquities from the Egyptian Museum were damaged by people working for the Egyptian Government:
Security officers in Cairo Egyptian Museum ripped the heads off two mummies from the Pharaonic era exhibited at the Cairo Museum during a robbery attempt staged during street protests, the two mummies mentioned by Dr. Zahi Hawass as being beheaded and severely damaged may be those of Yuya and Tjuya.
The Museum is naturally lit with glass windows on its roof. The criminals broke the glass windows and used ropes to get inside, there is a distance of four metres from the ceiling to the ground of the museum. The criminals who stole the jewellery from the gift shop are so stupid they thought they were robbong the museum jewellery items.... They went into the Late Period gallery and broke thirteen vitrines and threw the antiquities on the floor. Then they went to the King Tutankhamun galleries and they opened one case. The criminals found a statue of the king on a panther, broke it, and threw it on the floor.
In this blog you can see all the destroyed pieces and how they were before: