A police bullet ricochet may have passed through a bus during the London Bridge attack, according to reports.
They tackled him to the ground. Soon after police officers arrived on the scene and shot Khan at point blank range.
The BBC reported that photos taken an eyewitness show a round hole and shattered back window, while separate photos from the scene appear to show a round hole in the front window of the bus.
The eyewitness, who has been kept anonymous by the broadcaster, was on board the bus when he believes the ricochet passed through.
He said he heard and felt the impact of the bus' back window shattering and immediately fell to the floor.
"We are talking about a split-second of noise," he said
"In no more than a half-a-second I was on the floor."
Transport for London confirmed to the BBC that a bus was damaged during the incident.
The Independent Office for Police Conduct (IOPC) told the Evening Standard that they were investigating the cause of the damage to the bus.
An IOPC spokesperson said: "I can confirm that establishing the cause of the damage would be a line of enquiry for us."