English referee Michael Oliver has been offered police support after being abused by social media trolls following his Champions League penalty controversy.
Oliver and his wife Lucy were targeted in the aftermath of last week's quarter-final second leg clash between Real Madrid and Juventus.
Juventus were winning 3-0 after losing the first leg by the same score, but their hopes of a famous victory were spoiled when Oliver awarded a stoppage-time penalty to Madrid.
Juventus complained bitterly that Oliver had got it wrong and their goalkeeper Gianluigi Buffon was sent off for barging into the referee during their furious protests.
Buffon later said the 33-year-old Oliver had a "bag of rubbish for a heart".
Cristiano Ronaldo converted the penalty to eliminate Juventus and in the following days Oliver and his family were subjected to sickening taunts online.
His wife's mobile phone number was posted on social media and she received abusive text messages.
A Northumbria Police spokesperson said: "We are aware of threatening messages being posted on social media.
"This type of behaviour is completely unacceptable and those writing the messages need to be aware that they could be committing a criminal offence.
"Neighbourhood officers are in touch with the victims in this case to offer them support and ensure any further offences are reported to police."
The Professional Game Match Officials Limited (PGMOL) condemned the abusive messages aimed at the pair, while Twitter confirmed that it had removed a series of tweets from its platform over the weekend.
Oliver was fourth official at Saturday's Premier League match between Huddersfield and Watford.