Webber Natural Swimming Pool partly closed after mystery substance dumped into water

The Minneapolis Park and Recreation Board announced on Friday that Webber Natural Swimming Pool would temporarily close after someone poured an unknown white substance into the water.

According to MPRB , witnesses saw a person pour an unknown substance into the pool.

They had been acting irrationally, threatening staff and visitors both physically and verbally and had inappropriate comments, the board said.

The MPRB says it is working with Minneapolis police and the Minnesota Department of Heath to find out what was poured into the water.

A suspect has been identified by authorities. As of Monday morning, the lower pool and splash pad are open but the upper pool is closed.

The pool mimics the natural cleaning mechanisms of a pond or lake and is not chlorinated, which already could be a greater risk for visitors who are immunocompromised.

Related: Map: Where to find water parks, outdoor pools, and splash pads in the Twin Cities