Execution of police officer caught on video

The execution of a police officer is among the horrific scenes captured in a string of videos posted online in the aftermath of the Paris magazine massacre.

Clips recorded by eyewitnesses on smartphones showed two masked gunmen dressed in black firing what appear to be rifles as terrified onlookers fled.

One video circulated on Facebook shows the two gunmen standing next to a black Citroen car firing at distance at a police officer standing on the footpath on a tree-lined boulevard.