Dragons' Den star Duncan Bannatyne offered £50,000 on Twitter to anyone who would break the arms of a blackmailing tweeter who threatened to hurt his daughter, Hollie Bannatyne.
A tweet from Yuri Vasilyev read: "I'm looking for a GBP35,000 investments to stop us hurting your Hollie Bannatyne. We will bring hurt and pain into your life. We are watching her. She is very attractive.
The tweet was apparently posted from a cyber café in Moscow.
Following that, Vasilyev told Bannatyne: "Tweet using the hashtag £4money to confirm payment will be made."
Bannatyne reacted in fury, telling his 376,000 Twitter followers he was offering a reward for anyone could catch and injure the blackmailer.
"I offer £25,000 reward for the capture of the coward who calls himself @YuriVasilyev_ Double if his arms are broken first,” The Dragons Den star tweeted.
When one of his followers suggested that Bannatyne could be in trouble if Vasilyev was maimed at his behest, the 62-year-old continued: "I will gladly do my time."
The post was later removed but Bannatyne said in a statement: "My family is well protected but I take any threat to them very seriously and will do all I can to ensure the person or people involved are caught."
Within minutes of Bannatyne's reward offer, his followers had found an email address and Facebook page for the Twitter account.
Bannatyne then tweeting his blackmailer: "My people are getting closer to you every minute, run and hide you little coward in Moscow.
"Go home to your mum and cry we are closing in on you little boy."
Durham Police confirmed that Bannatyne had reported the threat and agreed that blackmail tweet appeared to originate from an email address in Russia. Detectives are investigating.
Bannatyne, who was born in a council house in Clydebank, Scotland, has business interests including health clubs, hotels, media, property and transport. His fortune is estimated at £430m.
The fiasco has sparked debate on Twitter.
“Duncan Bannatyne is hiring a bounty hunter through Twitter. How recruitment has changed,” 2MRep tweeted.
“Duncan Bannatyne has offered a £30k reward for the arrest of an anonymous tweeter. Suddenly, Twitter's interesting again,” wrote FatRoland.
“Duncan Bannatyne has gone all Tony Soprano via Twitter. Horrible that some loon is threatening his family but report it to the police,” advised mattmusic78.