The alleged killer of conservative activist Charlie Kirk wore a costume of President Donald Trump for Halloween, unearthed social media images reveal.

Tyler Robinson, 22, was seen dressed up in the outfit in a 2017 post shared by his mother Amber, when he would have been around 14.

The image shows him beaming at the camera while stood next to his younger brother.

Robinson was taken into custody on Thursday night in southern Utah after having allegedly confessed to killing Kirk, who died after being shot in the neck while speaking at a Utah Valley University event on Wednesday.

Robinson was a student at Utah State University on a scholarship, insiders confirmed to Daily Mail. He was identified as the main suspect in the shooting and remained at large for a day and a half.