SALEM – The Boston man who allegedly stabbed a Lynn man to death in Salem on Wednesday pleaded innocent to murder charges in Salem District Court on Friday.Jonathan Rivera, 21, of 20 Ruggles Ave., was ordered held without bail by Judge Robert Brennan for allegedly stabbing Shaundell Turner, 30, of 382 Essex St. Rivera is due back in court April 28 for a pre-trial hearing.Rivera allegedly stabbed Turner once in the chest around noon Wednesday near 50 Palmer St. in Salem, according to Steve O’Connell, spokesman for Essex District Attorney Jonathan Blodgett.Turner’s female companion called 911 at 12:07 p.m. and told Salem police that she was on her way to the police station, which is about a half mile from Palmer Street, with Turner in her car. Turner was then transported from the police station to Salem Hospital, where he was pronounced dead at 1:31 p.m. Salem Police Lt. Conrad Prosniewski said Wednesday the woman is not a suspect.”We also know that the girl knew both of them,” he said. It was not clear why the companion took Turner to the police station instead of the hospital.Rivera fled the area, but police tracked him down late Thursday afternoon at a Ramada Inn on Morrissey Boulevard in Dorchester, where he was arrested without incident.Turner attended Lynn Vocational and Technical Institute and is said to have been employed as a roofer. According to investigators, the motive in the fatal argument was still unclear and is under investigation.The case will be prosecuted by Essex Assistant District Attorney Kristen Buxton and Rivera will be represented by Attorney Edward Hayden of Lynn. Salem Police and State Police detectives assigned to the district attorney’s office are leading the investigation.