Syrian-born gunman Ahmad Alissa, 21, was known to FBI
Ahmad Alissa of Arvada, Colorado opened fire at the King Soopers grocery store at 2.40pm
He killed two people in the parking lot before entering the store, where he killed another eight people
His motive is still not known; when he surrendered to police, he asked to speak to his mother
In Facebook posts over the last 18 months, he complained that he didn’t have a girlfriend and hated Trump