UEFA has condemned the online abuse aimed at Michael Oliver and his wife after the English referee awarded a decisive stoppage-time penalty to Real Madrid against Juventus in their Champions League quarter-final, second leg last week.
"UEFA strongly condemns the abuse directed at Michael Oliver and his wife," European soccer's governing body said in a statement.
"We have been in contact with them to offer our support and we trust the relevant authorities to take action against those individuals who have behaved inappropriately both on and off social media."
Juventus, who had wiped out a three-goal deficit from the first leg, were furious when Oliver awarded a soft penalty for a foul by defender Medhi Benatia on Real forward Lucas Vazquez.
Cristiano Ronaldo converted the spot kick to make it 3-1 and send Real through to the semi-finals 4-3 on aggregate.
The BBC reported on Sunday that British police were investigating threatening text messages sent to Oliver's wife Lucy, whose Twitter account was also targeted with threatening and abusive messages.
The 33-year-old Oliver was bitterly criticised by some Juve players after the match, with goalkeeper Gianluigi Buffon saying the official was not prepared for such a high-profile game and should instead have been eating crisps in the stands.
Buffon lambasts Oliver after the game
Buffon, who was sent off for his furious protest, said that Oliver had a "garbage bin" instead of a heart.
On Saturday, Buffon said in an interview that he would repeat the comments all over again but in "more civil" language.
"I am a human being who puts passion, sentiment and anger into what I do," he said.