Police say they've arrested the person who left a package outside a Tennessee home that exploded after being opened, killing a retired couple.
The suspect is the couple's son-in-law, 49-year-old Richard Parker.
Police say he personally delivered the package to Jon Setzer, a retired lawyer, who was killed almost immediately after opening it on Monday.
His 72-year-old wife, Marion Setzer, has also died from the injuries she suffered in that blast.
CNN's Jean Casarez is OutFront.