When French Egyptologist Olivier Perdu saw a fragment of a pharaonic statue on display in a Brussels gallery last year, he assumed it was a twin of an ancient masterpiece he had examined in Egypt a quarter of a century earlier.

The reality was an even more remarkable coincidence: the fragment was part of the very same artifact - a unique 6th century B.C. statue hewn from pale green stone - that Perdu had received special permission to study in Cairo in 1989.

The statue, a 29 cm-high (11 inches) representation of a man wearing a pharaonic headdress and holding a shrine to Osiris, the god of the afterlife, was smashed by looters who broke into the Cairo Museum during the 2011 uprising against Hosni Mubarak.

Its top portion had been missing since then.

"I was just astonished," Perdu told Reuters. "Through examining all the stains and irregularities I could conclude that it was indeed the same piece.

"What I had between my hands in Brussels was the object that I had studied in the Cairo museum in 1989."

Thanks to his chance encounter, the piece excavated in 1858 has found its way back to Egypt. Horrified to learn he had purchased a stolen artifact, the buyer offered to surrender it right away, Perdu said. It is now back in Cairo, where conservation experts have reunited it with the rest of the statue.

Antiquities theft has flourished in Egypt in the three years of chaos since the 2011 uprising, robbing this ancient civilization of an indeterminate amount of heritage stolen from museums, mosques, storage facilities, and illegal excavations.

A small group of government employees tasked with scouring the internet in search of stolen treasures put up for sale has seen its work increase dramatically following the antiquities crime wave that accompanied the political upheaval of 2011.

In a few cases, thanks to serendipity, experts have spotted Egyptian artifacts in auction houses and private collections in the West and worked for their repatriation.

But while Egypt has recovered about 1,400 artifacts to date, it faces a struggle to get back all that has been lost.

There is no record of just how many antiquities have gone missing. Many were taken from illegal digs, and there is no way to know that they even exist.

"Most of them are not registered, because they were excavated by criminal gangs, not by specialists," said Ahmed Sharaf, head of museums at Egypt's antiquities ministry.

Swathes of the desert are now pockmarked with unauthorized digs, where thieves have used shovels and backhoes in search of buried treasure. Some have even dug tunnels to break into untapped antiquities sites without attracting attention.

Though officials claim improved security is curbing the theft, pieces continue to go missing, even from well-guarded sites. Just this month, two ancient statues were stolen from a storage facility at Luxor temple in southern Egypt.

"In the last three years, the sale of stolen antiquities has flourished - inside Egypt and abroad," said Sharaf.

ANTIQUITIES LAUNDERING

It's not just pharaonic artifacts that are being stolen.

Muslim rulers dating back to the seventh century left their mark on Egyptian architecture, and since 2011 thieves have torn decorative pieces out of mosques and other Islamic monuments in central Cairo.