Thefts took place between April 10 and 12, and when a number of museum staff returned to the building on April 12, they fended off further attempts by looters to enter the museum and had to wait till April 16 for the deployment of the U.S. forces around the museum. A special team headed by Marine Col. Matthew Bogdanos initiated an investigation on April 21. His investigation indicated that there were three separate thefts by three distinct groups over the four days. While the staff instituted a storage plan to prevent theft and damage (also used during the Iran–Iraq War and the first Gulf War), many larger statues, steles, and friezes had been left in the public galleries, protected with foam and surrounded by sandbags. Forty pieces were stolen from these galleries, mostly the more valuable ones. Of these only 13 had been recovered as of January 2005, including the three most valuable: the Sacred Vase of Warka (though broken in fourteen pieces, which was the original state it was found in when first excavated), the Mask of Warka, and the Bassetki Statue.