A 46-year-old Bronx man has been indicted by a Queens County grand jury for attempted murder, assault and other crimes for allegedly stabbing two men in their 70s on a subway in July, one of them a good Samaritan who had tried to stop the unprovoked attack, prosecutors said.

Patrick Chambers has been held since his arrest following the July 5 attack, part of which was caught on camera. If convicted, he faces up to 25 years in prison. He was arraigned Friday before a Queens Supreme Court Justice who set his return date for March 2021.

Prosecutors say Chambers was seen sitting in the train holding a knife in one hand and a pair of scissors in the other shortly before 7:30 a.m. the day of the attack. The train was near 52nd Street and Roosevelt Avenue at the time.

Suddenly, without provocation, Chambers started to yell at a 71-year-old man sitting across from him, prosecutors say. Then he allegedly got up and stabbed him. Both Chambers and the victim fell to the floor, at which point the suspect allegedly continued to stab the other man. A 73-year-old good Samaritan stepped in to try and stop the assault he ended up with a sharp blade puncture to the chest and wrist, prosecutors say. Seconds later, the suspect ran toward the other end of the train car and moved to an adjoining car.

He was cuffed immediately, prosecutors said. Cops allegedly found a knife in his pocket that appeared to have blood on it. They also recovered a pair of scissors that had been sitting near a puddle of blood in the subway car.

Both victims were taken to a local hospital for treatment. The 71-year-old man had a large laceration to his abdomen and chest; he lost about 2 liters of blood and had to undergo emergency surgery. No update on his condition was immediately available Tuesday.

"The defendant in this case is accused of stabbing a 71-year-old man in an unprovoked attack on the train. When another commuter tried to intervene, he too was viciously assaulted," Queens District Attorney Melinda Katz said in a statement. "This was a senseless act of violence that put both victims at grave risk. The defendant is in custody and will be held accountable for his alleged actions."