The suspect is described as a black man, between 19 and 21 years old. He is said to be skinny with dark skin, standing about six feet tall.
He was wearing a blue baseball cap, and was wearing a green polo shirt with an orange polo logo, blue jeans and house slippers.
Police say Makadji was sitting with friends on a park bench when a gunman approached and demanded money. They say the victim apparently didn't understand what was going on because of a language barrier.
The gunman began screaming at him, pistol-whipped him over the head, and then shot Makadji in the chest.
The gunman fled.
Makadji had been in the United States just three months, and his family and friends say he came to Philadelphia on a quest for the American dream.
"They just killed him," said family friend Ada Diawara, struggling to speak through her tears.
Seck Amadou, a close friend of the victim, was one of the two others there when it happened.
Amadou says when the gunman shot his friend, he and the other man simply ran as fast as they could.
"He tried to shoot me and shoot my friend," Amadou said.
Anyone with information is asked to call Philadelphia Police at 215-686-3334