According to reports, the Uzbekistan native told policemen during interrogation that he was happy about what he did.

Authorities also say that he left a note in his truck saying that he carried out the attack on behalf of ISIS.

CNN also reports that Joon H. Kim, the acting US Attorney for the Southern District of New York, said that the 29-year-old was charged with “charged with providing material support to ISIS, violence and destruction of motor vehicles.”

Investigators also revealed that over 90 ISIS propaganda videos was found in a cell phone which was taken from Saipov’s apartment.

Tuesday’s attack has been described by many as the deadliest terror attack since September 2011.