It was a stroke of poetic justice that led homicide detectives to UMBC student John Gaumer, prosecutors told a Baltimore County jury Monday.

As Gaumer, 23, beat Josie Brown, 27, the mother of a young girl, to death Dec. 29 2005, on the side of Interstate 95, his cell phone inadvertently dialed her phone, recording forever the sounds of the “violent assault,” Baltimore County Assistant State?s Attorney Sue Hazlett told jurors during opening statements in Circuit Court.