Matthew and Eric Early, both 18, from the 100 block of South 49th Street, are wanted for the shooting on Wednesday night, which was caught on surveillance camera.
Police say the victims, a 36-year-old man and a 30-year-old man, got onto the westbound SEPTA El at 15th and Market streets around 10:40 p.m.
While on the train, an argument erupted. Investigators say the victims were fans of the Chicago Bulls and were celebrating the team's victory.
Lieutenant John Walker from West Detectives told Action News on Thursday, "It escalates when the young males began to use profanity. The -year-old says, 'listen man, this train is filled with people - there's young kids, there's ladies on here. You need to watch your mouth, young boy.'"
At about one minute into the surveillance video, the train stops at 46th and Market Street and the Early brothers exit onto the platform.
Surveillance cameras were rolling as one of the brothers, who was wearing a blue, puffy vest, turned around, pulled out a gun, and fired.
Police have not said which of the brothers pulled the trigger.
Another camera showed the victim being hit and falling to the ground as the gunman, and his brother, flee.
That bullet went through that victim's stomach and hit the 30-year-old man in the right thigh.
Both victims are expected to survive. Police say the 36-year-old victim rode the El train to 52nd Street, got off and went to a friend's house. That friend then drove him to the hospital.
The suspects were described by police as:
Suspect #1: (Gunman) Black male, 16-19 years-of-age, thin build, dark complexion, no facial hair, wearing a blue puffy vest over a gray hooded sweatshirt and black pants with a white stripe.
Suspect #2: Black male, 16-19 years-of-age, 5'11"-6'0", thin build, dark complexion, no facial hair, wearing a gray hooded sweatshirt, and blue jeans.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), send a text message to PPD TIP (773847) or through phillypolice.com.
People were shocked when they found out this shooting may have stemmed from an argument over basketball.
Lisa Sawyer of Northern Liberties tells us, "Philly is a tough sports town, but no it doesn't surprise me. Just a shame, and you know ... my prayers are with [the victim] and his family. It's horrible."
"I thought it was very crazy. I thought it was very, very stupid," said Gary Greene of West Philadelphia. "To do something like that over a basketball game? Come on now."
Fred Brown, also of West Philadelphia, says, "A game. Hey, I am a Sixers fan, you know, my goodness. Suppose it was over something serious?"