Prop Ben Flower has received death threats after punching a defenceless Lance Hohaia in Sunday's Super League grand final between St Helens and Wigan.
Flower was yesterday handed a six month ban for his actions which saw him sent off just two minutes into his side's defeat.
A series ofabusive Twitter remarks were posted on an account on Tuesday, directed to Flower, the BBC reports.
Other Twitter messages said that Flower "deserves to be shot", adding that he is a "dead man".
Greater Manchester Police (GMP) tweeted: "We've been made aware of abusive social media activity about the Rugby League Grand Final. Please be reassured that we are looking into this.
Yesterday Flower was handed a six month suspension after the Rugby Football League found him guilty of "violent and aggressive punching" when he struck Hohaia.
Flower's punishment amounts to a 13-game ban, comprising two pre-season trials, Wigan's World Club Challenge meeting with Brisbane Broncos in February and the first 10 games of the 2015 Super League season.
Flower stunned the 70,000 crowd at Old Trafford when he landed a right hook on St Hohaia, who was motionless on the ground just two minutes into the match. The Wales international had moments earlier reacted to an off-the-ball forearm strike from Hohaia by knocking him to the ground.
Hohaia had earlier accepted a one-match ban after being charged with striking.
Wigan rugby general manager Kris Radlinski said Flower won't appeal against his ban, which is the second heaviest handed out in the Super League.
Terry Newton, the late former Britain hooker, was suspended for 10 matches for knocking out a player and breaking the cheekbone of another while playing for Wigan against St. Helens in 2005. The ban was extended to seven months when Newton's appeal was rejected.
