Const. Jason Nevill was also charged with fabricating the evidence against the victim and obstruction of justice.
Nevill initially maintained that Barrie resident Jason Stern had attacked him with intent to resist arrest in November 2010.
However, charges against Stern, now 28, were dropped after video surveillance emerged appearing to show the officer attacking him without provocation and beating him even after handcuffing him.
The incident occurred after Stern's friend broke a Christmas ornament at the mall.
Stern is suing Nevill and the mall for $1 million, arguing he sustained permanent physical and emotional injuries from beating.
© 2013 The Canadian Press