On March 23, the world once again watched in shock and horror after a terror attack struck London, England. According to multiple reports, a man drove a car into a crowd of people in front of the Parliament building, killing four people, including a London police officer.

According to CNN, fifty-two year-old Khalid Masood drove his car through a crowd before stabbing unarmed police officer Keith Palmer in front of the Parliament building. Masood was shot dead by London police before he could continue his attack. CNN noted after the attack that “It was the first mass-casualty terrorist attack in Britain since 2005 when 52 people and four attackers died in the July 7 bomb attacks on the London public transportation system. The use of a vehicle as a weapon of terror echoed the methods used in the past year by attackers in Nice and Berlin.”

According to the BBC, dozens of people from at least twelve different countries were injured in the attack, and one of the people killed was an American man from Utah.

British Prime Minister Theresa May said that “there was no prior intelligence of his intent or of the plot.” Masood was previously known to MI5 and was once investigated due to concerns about violent extremism but was considered “a peripheral figure,” according to May. Twelve people were arrested following the attack, but nine were released. London Deputy Commissioner Mark Rowley stated that 2,700 items had been seized in the investigation, including “massive amounts” of computer data.