Civilian gun ownership is illegal under Mexican law unless the owner purchases the weapon from a special shop run by the country’s Department of Defense.
The strictest of gun laws restrict citizens from defending themselves.
The massacre unfolded after gunmen arrived in two vans outside a private home in the San Rafael area of Celaya in Guanajuato State.
Heavily armed gunmen broke into the wake and attacked the mourners at around 9pm on Thursday January 7, killing at least nine people, local authorities said.
Another person was injured in the attack and was taken to hospital.
But there were reports the death toll could be as high as 13.