Police are still trying to determine who dumped a black bag  containing medical waste with a note for police, at the behavioral health center at Westchester Medical Center in Valhalla yesterday. Officials have not released details of the message and would only say it contained a threat toward police.

The medical waste is the latest suspicious package found in Westchester. Back on Friday, a suspicious silver package left on the Metro North train tracks in Irvington forced the Hudson Line to shut down for nearly 2 hours. Officials never said what was in that package, but said the Westchester County Bomb Squad detonated it as a precaution. There were no injuries there and there have been no arrests. It's unclear whether that package was dropped or intentionally left on the tracks.