In the aftermath of the Christchurch mosque shootings at Al Noor Mosque and Linwood Islamic Centre in Christchurch, New Zealand on 15 March 2019, it was discovered that the perpetrator, Brenton Harrison Tarrant of Grafton, New South Wales, Australia, had interacted with Cottrell's United Patriots Front (UPF) on its Facebook pages. He affectionately called Blair Cottrell "Emperor Blair Cottrell" and celebrated Donald Trump's victory as President of the United States in the 2016 presidential election, as well as donating to the UPF and threatening a man from Melbourne, Victoria, Australia over criticism of the organisation in 2016. Cottrell had distanced himself from Tarrant and denounced his attacks, stating he didn't know him. He conceded it was possible that a UPF member did meet him at one point. Tarrant was also offered to join the Lads Society, a fight club also led by Cottrell, but declined.