For the first time in modern history, the murder rate for Britain’s capital surpassed that of New York City.

A total of 44 murder investigations were conducted in London from January to March of this year—already more than one-third the number of homicides that occurred in one year from April 1, 2016, to March 31, 2017, according to statistics from the London Metropolitan Police.

The New York City Police Department looked into 18 killings in January, declining to 11 in February, and 21 in March. For London, the number of murder investigations was eight in January, 15 in February, and 22 in March.

Most of the murders—31 of the 44 investigated—were the result of knife stabbings. The number of fatal and non-fatal stabbings has increased despite a city-wide effort to take knives off London’s streets. In July 2015, the Metropolitan Police launched Operation Sceptre “with the aim of reducing knife crime and the number of families affected by knife crime across the whole of London,” according to its website.

In total, the operation has conducted nearly 5,800 sweeps and confiscated almost 400 weapons. Yet total crimes involving knives in London increased 34 percent from 2016 to 13,000 in 2017.

A former London police officer told BBC News the statistics are proof that “London’s violent traits have become a virus.”