NEW YORK CITY – New York City police have determined there was no criminality by Shake Shack employees after three officers drank milkshakes believed to be contaminated with bleach.

NYPD’s Chief of Detectives tweeted early Tuesday that the determination came after a thorough investigation.

A union had said the officers stopped at a Shake Shack in Manhattan on Monday evening and determined a toxic substance had been added to their beverages.

Another union said the officers went to a hospital for treatment but weren’t seriously harmed.

 Shake Shack tweeted that it was horrified by the reports and was working with police.