SALEM – A Lynn man believed to have robbed the St. Jean’s Credit Union over a two-month span was one of two people indicted on separate cases Friday afternoon by an Essex County grand jury.Derek Christiansen, 34, of 113 Franklin St., #5, Lynn, is charged with four counts of unarmed robbery, a crime that carries a potential life sentence in state prison.On Feb. 7, Christiansen allegedly stole about $300 from the St. Jean’s Credit Union at 527 Western Ave. in Lynn.Around 5 p.m., a man with blond hair and wearing a white baseball hat with red trim and a light colored jacket entered the bank, walked up to the female teller and handed her a note demanding money and fled with some $300, leaving behind the note.The security photo captured the robbery on the video.Then on March 5, the robber returned to the bank at about 8:30 a.m. again, passed a note to the same teller demanding cash and fled with about $900.On March 18, the same robber returned again to the bank at about 9:33 a.m., wearing a gray hooded sweatshirt over his head. He handed the teller a note demanding cash and fled with about $1,000 toward Franklin Street.Then on the afternoon of March 24 the lone robber returned once again wearing a baseball cap to the bank, again handed a note demanding money and fled with about $1,000.Christiansen was arrested the following day after a police officer recognized the lone robber from the video from one of the bank robberies.In each of the holdups no weapon was displayed, all four notes were left behind in the bank and the robbery was captured on the security video.The indictments handed up Friday now move the case from Peabody District Court, where Christiansen pleaded innocent, to Salem Superior Court.In the meantime, he remains held at the Middleton Jail on $50,000 cash bail.Assistant District Attorney Jean M. Curran is prosecuting the case for the commonwealth.Also indicted was Ernest Copoulos, 50, of 115 Lowell St., Apt. 10, Peabody, charged with trafficking over 100 grams of cocaine and possession of cocaine with the intent to distribute concerns his arrest in January.Police stopped Copoulos in his vehicle in Newbury on Jan. 8 and reportedly seized 13 plus grams of cocaine from his person.Authorities then executed a search of his home and reportedly discovered over 100 grams of cocaine inside his home along with other drug related items.A conviction of the trafficking charge carries a minimum mandatory punishment of 10 years in state prison.