A Chelsea man has been arrested in connection with six recent bank robberies in Worcester in which police say he sometimes threatened to return and shoot any teller who called for help.James Monteiro, 41, faces arraignment today in Worcester District Court on four counts of unarmed robbery, one count of armed robbery and one count of attempted unarmed robbery.The holdups occurred over the past few weeks at Bank of America, Santander Bank, Country Bank and TD Bank North branches.Police said Monteiro would wait in line, then pass a note to a teller, demanding money.