This is a woeful state of affairs. The story is as summarised by Sibanu on shortnews (I added plain-clothes as that was not known at the time):
“For those of you who aren’t aware of the background to the story, it appears that a man in a thick coat (in summer) was persued by (plain-clothes) police in the London Underground. The police shouted at him to stop, but he didn’t and continued to run toward a stationary train. Four policemen chased him and tackled him to the ground, where one of the policemen immediately shot five rounds into the back of the mans head, killing him instantly. This is summary execution, no more, no less, whether the man was connected with the terrorists or not, and as such the policemen should be charged with intentional homicide. Our morals and standards are shattered beyond revertion. This if anything will prove to further legitimise the terrorists cause, in their eyes.”
A quote from the following BBC article:
Mr Pereira, said Mr Menezes, who was from the city of Gonzaga in Minas Gerais state, had lived in London legally for at least three years and was employed as an electrician. The BBC’s correspondent in Brazil, Tom Gibb, said Mr Menezes had lived for a time in a slum district of Sao Paulo and that could explain why he had run from the police.
He said: “The murder rates in some of these slums are worse than in a lot of war zones and that could explain why, when plain clothes officers pulled a gun on him, he may have run away.”
The BBC story can be found here.