The motive for the daylight killings remains unclear
Four Coptic Christians have been shot dead in broad daylight at a jewellery shop in a busy district of the Egyptian capital, Cairo.
Details remain sketchy, but witness accounts speak of two men, wearing wigs and sunglasses, entering the shop and opening fire with automatic weapons.
The motive for Wednesday's murders is still unknown because the killers did not appear to have stolen anything.
There are fears the attack may have been sectarian or even political.
The manner and the timing of the crime has shocked residents of Cairo, says the BBC's Arab Affairs Analyst, Magdi Abdelhadi.
The shop's owner and three of his assistants were killed in the attack. All four were Christian Copts.
The killers then sped away on a motorbike.
Egyptian jewellery shops owned by Christians have, in the past, been looted by Islamist militants to finance their insurgency, reports our correspondent from the Egyptian capital.
But that has not happened since the government quashed militant groups during the 1990s.