A federal judge has sentenced a drug dealer to death for the 2005 killings of three people in Bridgeport, Conn., in a turf dispute involving crack-cocaine sales. US District Judge Janet Bond Arterton in New Haven imposed the sentence Monday on Azibo Aquart, 31. A federal jury convicted Aquart of racketeering murder and conspiracy and decided on the death penalty last year. It is the first time since the federal death penalty was reinstituted in 1988 that the death penalty has been imposed on a federal defendant in Connecticut. Prosecutors said Aquart and three other men who pleaded guilty to murder were involved in the beating deaths of Tina Johnson, 43, James Reid, 40, and Basil Williams, 54, in Johnson’s apartment.