I think they are referring to the two guys who killed the black man by tying him to their truck and dragging him.
I will say this- any non-police officer who tries to ‘citizen’s arrest’ me had best be armed, willing to pull the trigger and have their will made, because I WILL assume they are trying to kidnap or hold me up. If they don’t have a uniform and a badge and I’m not on private property where I shouldn’t be, it’s assault and any defense is justified.
There was an episode of The Andy Griffith Show where Gomer attempted a Citizen’s Arrest.
He was yelling Citizen’s Arrest! Citizen’s Arrest!