Boston GlobeFather convicted of 1st-degree murder in death of Rebecca RileyBoston GlobeBROCKTON – A South Shore father of three was convicted today of first-degree murder for killing his youngest 4-year-old child with an overdose of psychotropic drug that he and his wife had nicknamed "happy medicine. ...Mass. dad convicted in OD death of daughter, 4The Associated PressHarsh diagnosis for Dr.