Jean Roy, 24,  was arrested yesterday for the murder of a Boston man on Walnut Street Sunday morning. 

John Micelin, 23, was shot and killed at 4 a.m. in front of 57 Walnut Street last week.

  Roy was arraigned in Somerville District Court this morning on a charge of first degree murder.

“We allege that the defendant shot this victim at very close range while inside a car,” District Attorney Leone said. “This arrest is another example of the important cross-county collaboration between agencies and departments – including Massachusetts State Police, Somerville Police, and Boston Police – to investigate crimes of gun violence on our streets.”

According to authorities, at approximately 4 a.m. on Sunday, May 6, Somerville Police received a call from a resident to report an injured person on Walnut Street in Somerville. Upon arrival at the scene, police found Micelin in a car unresponsive and suffering from a gunshot wound. Micelin and another victim, also suffering from gunshots, were transported to Massachusetts General Hospital by paramedics. 

Massachusetts State Police assigned to the District Attorney’s Office, Somerville Police, and Boston Police began an immediate investigation. Based on that investigation, it is alleged that Roy shot both men while inside a car. Last evening at approximately 10 p.m., a warrant was taken out for the arrest of Roy in connection with the Somerville incident. Hours later, Boston Police arrested Roy in connection with an unrelated incident in Boston.

  Authorities said the case remains under investigation.