To clear things up: the passenger pulled off the flight was a non-revenue-HE DIDN'T HAVE A PAID TICKET. Also, because the flight was overbooked they escorted him (without force) off the place but then he ran back on and that's when they called the police. Technically it's against United's policy to grab a passengeroommate but it was Chicago PD who did the actual grabbing so STFU about this
And I'm including the third leg too