LYNN – Two Lynn men were arraigned in Lynn District Court on Friday in a case involving heroin and gun sales in the South Common Street neighborhood.Jesse Butler, 20, of 435 Essex St., Lynn and John Martin Marino, 21, of 22 Grant St., Lynn, were charged with selling more than 28 grams of a Class A substance. Butler also faces charges of firearms trafficking, drug distribution and driving without a license.Both men were arrested after an investigation conducted by the Lynn Drug Task Force, the Massachusetts State Police and the U.S. Bureau of Alcohol, Tobacco and Firearms. According to reports, a witness tipped police off to the fact that Butler had taken over a Lynn-based heroin ring for his supplier who is currently in prison.An undercover police officer arranged to buy $300 of heroin from Butler late last month. That initial meeting led to Butler selling a gun through the undercover officer and arranging to buy two other firearms and ammunition.Police set up a meeting to exchange guns for heroin with Butler on Thursday. Marino accompanied Butler and both men were arrested in a parking lot on South Common Street. Detectives searched Butler at the Lynn Police Station and found two bags contain 25 grams of heroin. Butler told police that Marino, who was not carrying any drugs or weapons, had come along to protect him.