A 19-year-old man wanted on murder charges by authorities in Puerto Rico was arrested Friday in Lynn, the US Marshals Service said. Edgar Serrano, is accused of shooting and killing the manager of a fastfood restaurant during an attempted robbery in Juncos, Puerto Rico. He fled to Massachusetts, the US marshals said. Serrano was arrested Friday on Western Avenue on a warrant issued by a court in Puerto Rico. He will be detained in Massachusetts while he awaits extradition.Beth Daley can be reached at firstname.lastname@example.org. Follow her @Globebethdaley.