Charlie Kirk was shot in the neck as he spoke to students at a university campus in Utah on September 10.
Thousands of people were in attendance to watch Kirk, who was well known for his strong, right wing conservative opinions, debate students.
Whilst debating the issue of school shootings in America, Mr Kirk was shot in the neck with a bolt-action rifle from the roof of a nearby campus building.
A Utah Valley University police officer was watching the university campus crowd from an “elevated position” and identified the roof of the Losee Centre as a potential position for a gunman, Mr Gray said.
The officer found evidence on the roof immediately, he said, and spurred officers to direct their attention to surveillance video leading to the roof.
His death has sparked debate on the issue of free speech and hate speech in the US, with TV host Jimmy Kimmel suspended for comments made in the wake of his death.
