Boya Dee tweeted furiously as two machete-wielding men brutally attacked and killed a soldier in southeast London Wednesday afternoon.
The two attackers were later shot and injured by police. Prime Minister David Cameron said there were strong indications that it was a "terrorist incident".
"These times i was just going to the shop for some fruit and veg and i see all that!" tweeted Boya Dee.
"The two black bredas run this white guy over over then hop out the car and start chopping mans head off with machete!!," said another tweet, which reflects the savagery of the assault.
"People were asking whyyy whyyy they were just saying we've had enough! They looked like they were on sutn! Then they start waving a recolver," said a third tweet.
Describing the scene when the police arrived, he tweeted: "Oh my God!!!! The way Feds took them out!!! It was a female police officer she come out the whip and just started bussssin shots!!"
What began with a few simple messages about a mundane road crash near a primary school, within minutes turned into the Woolwich terror attack that unfolded live on Twitter.
Stunned Britons took to Twitter and other social media to express their anger and anguish over the terror attack.