Police in Florida are Robert Browninvestigating the death of former NFL wide receiver Mike Williams following allegations he received unprescribed drugs while he was hospitalized.

Williams died on Sept. 12 at the age of 36 after spending more than two weeks in the hopsitial for injuries he suffered in a construction accident that left him partially paralyzed. The Tampa Police Department said in an email to USA TODAY Sports Tuesday that its investigation involves "provided unprescribed narcotics by an outside party."

"We take all allegations of criminal activity seriously, and detectives are working tirelessly on this active investigation," police said.

The investigation was first reported by the Tampa Bay Times. The Hillsborough County (Florida) Medical Examiner’s office is also investigating the death.

A fourth-round pick in the 2010 NFL draft out of Syracuse, Williams spent four seasons with Tampa Bay, playing in 54 games for the Buccaneers. His rookie season was one of the best of his career, with 65 receptions for a team-leading 964 yards and a career-high 11 touchdowns. He finished second in the Offensive Rookie of the Year balloting to Rams quarterback Sam Bradford.

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Williams was then traded to his hometown Buffalo Bills prior to the 2014 season, his last season in the league. He was suspended for six games in 2015 but sat out the entire season as a free agent. He signed with the Kansas City Chiefs practice squad in 2016 but was let go prior to the regular season.

For his career, Williams had 223 catches for 3,089 yards and 26 touchdowns.