In chapter 7 of "Night", describe the scene Elie witnessed between the father and son.

The Jewish prisoners have been on-board a train, crammed in crowded cars, with no food for over 10 days.  They are starving and dying rapidly.  When the train stops briefly some workers throw some pieces of bread into the car.  Men immediately begin to fight over the bread.  The workers are amused and throw more bread. 

Elie sees an old man dragging himself toward the bread while holding another piece inside his shirt.  As he puts one piece in his mouth he is attacked by his son.  He screams "Meir, Meir, my boy! Don't you recognize me?"  His son continues beating him until he is dead and takes the bread from him.  After killing his father and getting the bread, he is also attacked and killed for bread.  You can read the exact details on page 68.