Two men accused of attacking and robbing a group of summer visitors this summer on an Oak Bluffs town beach were indicted by a Dukes County grand jury in superior court on Monday.

Trevor Byrn, 18, of Bethel, Conn., was indicted on single counts of armed robbery, assault and battery to cause serious bodily injury and aggravated assault and battery. Alex J. Daignault, 19, also of Bethel, Conn., was indicted on single counts of unarmed robbery and aggravated assault and battery.

Both men are currently free on bail, and will be arraigned sometime during the current sitting of the Dukes County Superior Court. According to police, Mr. Byrn and Mr. Daignault attacked a group of young men walking on the beach along Seaview avenue on the evening of July 4. When police arrived they found two victims, including one man who had been hit in the head with a rock and knocked unconscious.

The victims said they were attacked by two assailants, later identified as Mr. Byrn and Mr. Daignault, who robbed them of their wallets, cash and cell phones.

Also on Monday the grand jury indicted Victor Cruz, 28, of Edgartown, on a single count of trafficking Oxycodone. The Martha’s Vineyard Drug Task Force arrested Mr. Cruz in August after he was caught trying to exit the ferry at the Vineyard Haven Steamship Authority terminal with 182 Percocets and 47 Oxycodone pills.

The grand jury indicted Nelio Maciel, 35, of Oak Bluffs on single counts of trafficking cocaine and possession of cocaine with intent to distribute. Mr. Maciel was arrested by Oak Bluffs police in August after a patrol officer observed him making a drug transaction in the downtown area.

When police searched Mr. Maciel’s car they reportedly found 22 bags of plastic bags of cocaine; during a search of his home an additional 220 grams of cocaine and a large quantity of the illegal drug Ecstasy were also found.

The fall sitting of superior court began Monday and runs for four weeks. The Hon. Cornelius J. Moriarty 2nd, an associate justice of the superior court, is presiding over the session.