When police come knocking at your door, it spells trouble.

It happened to pop star Britney Spears on the last day of September, and she went on a rant on social media against fans who had tipped off cops about her provocative dance video posted on Instagram.

Fans got worried for the 41-year-old "…Oops, I did it again" singer when they saw her on the video dancing while swinging kitchen knives in each hand at the entrance of her California home, clad in a
salmon-colored polka dot crop top and white bottoms, New York Post reported.

She was twirling and twirling around while clanging the knives together. Fans thought it was "suicidal."

The visiting officers announced behind the door that they wanted to speak with Spears as part of a welfare check. It turned out to be a false alarm.

In a follow-up post, Spears wrote: "I know I spooked everyone with the last post, but these are fake knives that my team rented from Hand Prop shop in LA. These are not real knives. No one needs to worry or call the police."

In the United Kingdom, a yoga class at the Seascape Cafe had a concerned citizen calling the police early last month. The caller reported a mass killing upon seeing several people lying on the floor in the building, The Guardian reported.

Within minutes, police sirens were heard outside the North Sea observatory in Chapel St. Leonards, Skegness, Lincolnshire, around 9:30 p.m. on 6 September.

When police barged into the evening yoga class, the people lying on the floor meditating were surprised.

The Guardian quoted Lincolnshire police as telling the PA news agency: "We're happy to report everyone (of the yogis) was safe and well."