London’s head of police threatened to extradite U.S. citizens and other foreign “keyboard warriors” who violate the U.K.’s restrictive speech laws while posting rumors that fueled the country’s recent riots.

London Metropolitan Police Commissioner Sir Mark Rowley issued his warning last week when he said social media users could be charged with incitement, racial hatred and potential terrorist offenses for spreading rumors that helped spark a wave of riots following a deadly July 29 knife attack.  

“We will throw the full force of the law at people,” Commissioner Rowley told Sky News. “And whether you’re in this country committing crimes on the streets or committing crimes from further afield online, we will come after you.”

False reports online suggested a Muslim asylum seeker stabbed three girls to death and wounded eight others during last month’s attack at a Taylor Swift-themed dance event in Southport, a seaside town about 20 miles north of Liverpool.

Police came out later and named 18-year-old Axel Rudakubana as the suspect, saying the teen is a British-born citizen of Rwandan descent described as a Christian. He is facing murder charges in the mass slaying.

But the rumors had done their damage.

Rioters set out to vandalize businesses and clash with police, including outside of mosques and near the prime minister’s office in London. Violent confrontations between rioters and counter-protesters regularly broke out as well.

Over 900 people have been arrested and more than 460 charged since the riots erupted late last month, which have died down in recent days.

Commissioner Rowley said law enforcement has an interest in tracking down the peanut gallery on social media since the users’ speculation threw the country into turmoil.

“All of those offenses are in play if people are provoking hatred and violence on the streets, and we will come after those individuals just as we will physically confront on the streets the thugs and the yobs who are taking — who are causing the problems for communities,” Commissioner Rowley told Sky News.

According to the U.S. Embassy in Britain, the most recent extradition agreement allows Americans charged with terrorism offenses to be sent over to U.K. authorities.

British law says people can be culpable for terrorism by either planning or assisting in a terrorist attack.

U.K. regulators will be able to levy fines against tech companies next year that allow illegal or harmful content on their platforms.

• Matt Delaney can be reached at mdelaney@washingtontimes.com.