This has nothing to do with the Wii and everything to do with leaving a gun unattended.
Plus something is fishy here, if I were an investigator I would try to dig deeper into this - since when does someone point a Wii controler shaped like a gun at one's abdomen, even if they think it is a Wii controller? And before you say well this is a 3 year old, think a second - a 3 year old that knows how to pull a trigger? Something is wrong here, and I have this horrible feeling it is not the child that has pulled the trigger.
Currently Playing: Shin Megami Tensei: Devil Survivor Overclocked, Professor Layton and the Curious Village
Anticipating: Xenoblade, The Last Story, Mario Kart 7, Rayman Origins, Zelda SS, Crush3D, Tales of the Abyss 3DS, MGS:Snake Eater 3DS, RE:Revelations, Time Travellers, Professor Layton vs. Ace Attorney, Luigi's Mansion 2, MH TriG, DQ Monsters, Heroes of Ruin