New York City police have arrested a suspect in connection with a spate of stabbing attacks on the city’s subway that left two people dead, authorities said on Sunday.

Rigoberto Lopez is charged with one count of first-degree murder, two counts of second-degree murder, and two counts of second-degree attempted murder, the New York Police Department said on Twitter.

The four unprovoked attacks apparently targeted homeless people and took place on the A train or at stations served by it beginning on Friday morning.

Local radio station 1010WINS, citing police sources, said Lopez was taken into custody late on Saturday.

New York City Police Commissioner Dermot Shea told reporters on Saturday that 500 additional officers were being deployed to the city’s transit system “to make sure people feel safe.”