49-year-old Richard Parker placed a bomb in the home of Jon and Marion Setzer in Tennessee. He lived next door to them. Jon Setzer died when the package bomb went off and Marion died in the hospital after it went off. He was 74 and Marion was 72. Richard Parker was their son-in-law who is now charged with two counts of felony first-degree murder and two counts of felony premeditated murder. He was convicted of arson about 16 years ago, and served four years on probation, which made him a good suspect for the crime. There was also a note that they think was attached to the bomb that they found and investigated. Parker is now in custody.
http://www.cnn.com/2014/02/13/justice/tennessee-lawyer-letter-bomb-death/index.html?hpt=ju_c1