Mona Ethaway, an Egyptian journalist and blogger, has asserted that the damage reported to mummies and artifacts at the Egyptian Museum was the work of "the police and thugs of Hosni Mubarak." See
This is not as strange as it sounds. Other reports have it that Government security forces have been vandalizing property in order to justify a crackdown in the eyes of the public. In addition, it has been reported that the police opened up the jails to show the Egyptian public that chaos is the alternative to Mubarak's rule.
Certainly, the story about the looting of the museum seems a bit odd; it came amid other information that the museum was being protected by protesters and the army.