Why your Facebook friends are 'checking in' at Standing Rock

Tens of thousands of Facebook users across the U.S. have been falsely "checking in" at the Standing Rock Indian Reservation in North Dakota after a viral message claimed that investigators were tracking protesters on Facebook.

"The Morton County Sheriff's Department has been using Facebook check-ins to find out who is at Standing Rock in order to target them in attempts to disrupt the prayer camps," said a version of the message, whose origin was unclear and which was collected by the hoax-busting site Snopes.

"SO Water Protectors are calling on EVERYONE to check-in at Standing Rock, ND to overwhelm and confuse them."

But on Monday, the Morton County Sheriff's Department said the claim was a hoax.

"In response to the latest rumor / false claim circulating on social media we have the following response," the department said in a post on Facebook. "The Morton County Sheriff's Department is not and does not follow Facebook check-ins for the protest camp or any location. This claim / rumor is absolutely false."

Demonstrators have been stationed at Standing Rock for months to protest the planned path of a pipeline that they say could desecrate tribal lands and put their drinking water at risk.