Gun used to shoot 3 police linked to former Chicago cop

The gun used in the shooting of three Chicago police last week has been connected to a former Chicago cop, who most recently was a Lake County sheriff's deputy.

The firearm was originally bought by the 27-year-old deputy and ended up in the hands of Lamar Harris, a 29-year-old convicted felon who was killed during the shootout with police.

The identity of the former officer, who worked out of the Harrison district from 2013 to this past January, has not been revealed by police.

Law enforcement sources indicated the officer owned dozens of guns and are still trying to determine how his gun came into Harris' possession.