Date: 201705
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
Detector: Person Flight Attendant
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: This event played out over the course of about 45 minutes. It started with one of the Flight Attendants calling the cockpit saying a Passenger had grabbed her by the lapel of her shirt and pulled her towards him demanding to know if the American Flag pin on her collar was an ICE (Immigrations and Customs Service) pin. The suspect was aggressive towards the Flight Attendant. After she called; we went in lockdown and I made the assumption and told the FAs and FO that this was a Level 1 Threat. I notified Dispatch and began coordinating our arrival to ZZZ. After several minutes; and after looking at the Ops Binder; I realized that it was in fact a Level 2 Threat. The suspect continued to use aggressive language towards both female Flight Attendants but did not become more physically aggressive after the initial confrontation. The FAs told me that two Company Ramp Personnel were seated in front of the suspect and they had offered any and all assistance in case the suspect became more aggressive.We were only about 30 minutes from ZZZ when this started; the FO continued his flying duties and I coordinated with the FAs; Dispatch; Center and Ground Operations at ZZZ. It was a busy time for both of us and there was weather in the area to deviate around that added to the conditions at hand. The FO did a masterful job flying and talking with ATC; but I felt as though we were in and out of the green and yellow a number of times. In the descent; we decided to [advise ATC of the situation]. This really reduced the workload and distraction as ATC gave us direct ZZZ with deviations as necessary.Operating on the edge of the green and yellow; over a period of time; has a physiological effect that I never saw before. First off; there was an increased level of stress; not knowing if this guy was going to lose it and become combative; in which case would have meant an immediate divert; and in that case; would we then be intercepted and escorted to our destination. This along with the coordination quite obviously gets the adrenaline going. With that said; the one error that I know I made was taxiing about half-way into the Safety Zone before I realized there was no Marshaller in place to guide us in. I stopped; waited for him to come and the rest of the taxi in was uneventful.




Synopsis: B737 Captain reported a Flight Attendant had been grabbed by her shirt by an aggressive passenger. The Captain followed the procedures for a level 2 threat.