Police cars and vans and three armed police units are near a BMW and a lorry on Ridge Green which has been extensively cordoned off since around 6.30pm.
Nearby resident Rachel Windsor, 46, said: “It’s quite a nice estate so we don’t ever see police officers round here. I was just about to walk to Aldi when I heard this massive shot. I thought a bus had punctured its wheel.”
Passerby Michael Rozwadoski, 42, said: "I saw the helicopter and we were a little bit afraid, my daughter was terrified."
A neighbour, who did not wish to give her name or age, said: "I saw it too. It's amazing, it's relatively quiet around here all the time."
One man, 18, heard what sounded like a firework, and ran over to see police medics treating a man on the ground: “All I heard was a shout. It was really loud. The man was on the floor. His leg was up. They called the medic kit."
A nearby resident, a woman in her 50s, said: “It’s quite a shock, I suppose. It’s a bit unusual. It’s usually lovely and quiet.”
Another neighbour, a woman who did not want to give her name, said: “I think the whole thing is a tragic story. That’s all I’m going to say.”
A man, 60, said: “I heard a shot then I heard the helicopter and that’s it really. It seemed like a single gun shot.”
Wiltshire Police have been approached for comment.