Both Nelson and Abdullah bought a rifle (BB gun and .270 Winchester M70 Rifle).
While both Marge and Ahmed forbade both kids (Bart and Yussef) from doing something that was deemed bad, (Bart was with Nelson while Yussef watched his older sister Zohra undressing).
While three kids (Bart, Nelson, Ahmed and Yussef) tested the rifle on some things, two of them (Bart and Yussef) accidentally shot on the living beings (the bird and Susan Jones, although the bird was shot dead while Susan was just wounded from the shot).
After those incidents, both parents (Marge and Abdullah) were angry with their children (Bart, Yussef, Ahmed and Zohra).
Three persons (Apu, Hassan Ibrahim and Yasujiro Wataya) were involved with the awful incidents whose origins were from the other countries (Yasujiro gave the rifle to Hassan in Morocco before Yasujiro returned to Japan where he was investigated by the detectives about that incident, while Apu noticed both lizards that had come with his shipment of Bolivian donuts and escaped his store while he was putting them on the shelf).
Both Bart and Yussef defended from the people (Bart explained he loved and raised the lizards while Yussef admitted he injured Susan).