Screenshot of TrollStation’s YouTube video of the faux heist at National Portrait Gallery from July 2015.

Four members of the group behind the YouTube channel TrollStation received jail sentences on Monday at the City of London Magistrate’s Court for staging a fake heist at London’s National Portrait Gallery and a faux kidnapping at Tate Britain in July 2015.

The hoax, which caused panic and chaos and nearly resulted in a stampede, was staged at a particularly sensitive time, with the 10th anniversary of the London bombings approaching.

On July 5, 2015, the masked men burst into the National Portrait Gallery at about 3:30 pm and tried to remove paintings from the museum’s walls. When police arrived at the scene, the pranksters were already headed to Tate Britain, where they proceeded to film a fake kidnapping and another art robbery.

According to the BBC, all four members pleaded guilty to two counts of using threatening, abusive, or insulting words or behaviour with intent to cause fear of, or provoke unlawful violence.

Each received a jail sentence varying from 16 to 20 weeks for their involvement in the National Portrait Gallery stunt, and concurring eight week for the Tate Britain hoax.

“The hoaxes may have seemed harmless to them, but they caused genuine distress to a number of members of the public, who should be able to go about their daily business without being put in fear in this way,” said Robert Short, of the Crown Prosecution Service.

“We hope these convictions send a strong message that unlawful activities such as these will not be tolerated in London,” he added.

The ruling serves an additional blow to the group, who’s already seeing legal action taken against them. This past March, the founder of TrollStation was sentenced to 12 weeks in jail for the faux heists, and an additional 24 weeks for a separate prank that involved fake bombs.

The channel, which films pranks around London, is followed by some 718,000 subscribers.