Entertainer Justin Bieber is the subject of an assault investigation after a woman that claims to have been hit by a Nerf dart filed a police report for assault, reports TMZ.

Sources told the gossip site that the woman was a female employee of the venue where Bieber was performing and Bieber and his 3-year-old brother and 4-year-old sister were reportedly playing with Nerf guns and one of the sponge-like projectiles hit the woman.

The sources also told the site that the woman then reportedly told Bieber's people she was a security guard for the venue and was very angry. She then was said to have filed a police report, telling the Canadian police that she was hit by something.