In a shocking incident that unfolded on a packed local train at Malad station, Alok Singh, a 33-year-old junior college instructor known for his passion for math and statistics, was fatally stabbed after a disagreement over exiting the train. The assailant, as of now unidentified, launched the attack in full view of other passengers.

About 13,000 flights were cancelled Saturday and Sunday across the US, according to the flight tracking website FlightAware.

A second US citizen, Alex Jeffrey Pretti, was killed by Border Patrol officers in Minneapolis, weeks after another fatal shooting by federal agents. Footage shows officers tackling Pretti, who was holding a phone, and firing multiple shots even after he collapsed. Officials claim Pretti violently resisted disarming, but his family describes him as a caring nurse.