A police detective has described how officers found a shell casing and blue bubble gum that they used to link former New England Patriots player Aaron Hernandez to a June 2013 killing.

North Attleborough police Detective Michael Elliott is being cross-examined by Hernandez lawyer James Sultan on Wednesday.

Hernandez is charged with killing Odin Lloyd, who was dating his fiancee's sister.

Elliott said they were called by a rental car company worker, who told them several items had been removed from a car Hernandez rented and put in a trash bin.

Elliott said police searched the bin and found the shell casing attached to the gum.

Sultan questioned the way police handled the items.

Prosecutors have said Hernandez bought blue bubble gum shortly before the killing.