Chester County District Attorney Tom Hogan said Monday that 23-year-old Sean O'Neill Jr., of Glen Mills, failed a court-ordered drug test and may have fled the country.
O'Neill served time as a juvenile for killing his best friend with a shotgun in 2006 during a party at O'Neill's home. He was currently on parole from a drunken driving conviction for crashing his SUV into a house in 2011 while three people were sleeping inside.
Hogan said that while on parole, O'Neill tested positive for alcohol and illegal drugs.
His father, former builder and pub owner Sean O'Neill Sr., was deported to Ireland last year after serving time on a federal weapons charge.