4:08 PM PT -- Detroit PD tells TMZ Sports ... "This investigation continues to evolve, and new information has come to light that we are actively addressing."
"We take every investigation seriously, especially when new allegations and facts emerge, and we are committed to acting in a swift and transparent manner."
The statement continued ... "Once new facts are confirmed, we make the necessary changes in our decision-making process."
"Let it be clear: no one in the City of Detroit is above the law. Anyone who commits a crime will be held accountable, regardless of their position or status."
Detroit Lions receiver Jameson Williams narrowly escaped being arrested for carrying a concealed weapon earlier this month ... and police are now investigating why he was let off the hook.
23-year-old Williams was riding around Detroit with his brother after midnight on Oct. 8 ... when the vehicle was pulled over for a traffic violation.
During the stop, Williams' brother told cops there were two guns in the vehicle ... and one was located under the NFLer's passenger seat.