Justin Bieber is reportedly being investigated for assault -- with a Nerf gun. According to TMZ, while on tour in Ottawa, Canada, Justin was playing with his 3-year-old brother and 4-year-old sister when apparently a Nerf dart hit a female employee at the venue. The woman reportedly got upset & told JB's crew she was a security guard for the venue.

However, Bieber is trying to settle fans concerns: