A320
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Distraction; Situational Awareness
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Passenger Misconduct
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance; General Police / Security Involved
Human Factors
On the STAR; we were called by the flight attendants about 10 minutes prior to descent regarding a disturbance in the cabin. A female passenger had claimed a male passenger had assaulted her and would not stop touching her. They did not report injuries but requested the police to be at the gate upon arrival. We tried immediately after the call to reach Operations with no answer.At some point during this; ATC issued descend and maintain clearance to FL220. After initiating the descent; the captain resumed attempting to contact Operations. While on the radio with Operations; ATC issued another descend clearance to 17;000 with an expedite descent. I set open descent and read back the clearance. Just prior to returning from speaking with Operations; ATC issued another clearance; this time descend via the STAR. I input 3000 and continued the descent. The captain returned to state he had reached Operations and the police would be present. Shortly after this; ATC instructed us to maintain 13000. I realized we were below the crossing restriction and initiated a climb to 13000. We were in VMC conditions and ATC verified we had returned to descend via clearance and climbed to 13000. No further communication occurred and we thanked ATC for their help.The combination of flight attendants calling; multiple altitude clearances and a brief expedite clearance caused me to forget to set managed descent from open descent upon receiving the descend via clearance. I knew immediately when queried by ATC what had occurred. This was a combination of multiple distractions and varied clearances. Diligence when one pilot is handling a problem outside of normal flight is required. Perhaps once established on an arrival after initial descent expedited descents shouldn't be issued unless for immediate traffic avoidance.
A320 first officer reported that a disturbance in the cabin caused a distraction that resulted in a deviation from the descent profile clearance.