The son-in-law of a Tennessee couple killed by a bomb at their home has been arrested, federal and state authorities said on Thursday.
Richard Parker, 49, lives behind the house of the victims, estate-planning lawyer Jon Setzer, 74, and his wife Marion, 72.
"They have the same driveway," one official said.
Officials declined to say what led them to Parker or what the motive may have been.
They said the bomb that exploded in the house was placed at the home and was not sent through the mail or shipped.
Jon Setzer was killed in Monday's blast while his wife died from her injuries at the hospital on Thursday.