Sexton, 33, of Warwick, Rhode Island, and Randall Daluz, 36, of Brockton, Massachusetts, known by the nickname “Ricky” or “Money,” have been charged with three counts of murder and one count of arson in connection with the deaths. Investigators have described the slayings as a drug deal gone bad. Sexton and Daluz have pleaded not guilty.

The charred bodies of Nicolle A. Lugdon, 24, of Eddington, Daniel T. Borders, 26, of Hermon and Lucas A. Tuscano, 28, of Bradford were found in a burning rental car on Aug. 13, 2012, at 22 Target Industrial Circle in Bangor.

Sexton took the stand in his defense Monday as the trial spilled into its fourth and most likely final week. He told a packed courtroom that Daluz killed Borders by accident when he “hit him in the head with the barrel of the .380 pistol.” Sexton said Daluz killed Tuscano and Lugdon “deliberately.”

His testimony of how he and Daluz came to Maine matched that of previous witnesses in most aspects. Sexton rented a car in Rhode Island and picked Daluz up in Massachusetts on Aug. 11, 2012. The two came to Maine to sell drugs and spent much of the evening of Aug. 12, 2012, at Carolina’s Sports & Spirits in Bangor.

Sexton, however, denied that two guns — a derringer and a .380 pistol, which both have been tied by a firearms expert to the slayings — were on the bed of a Brewer motel room as Katelyn Lugdon, 19, formerly of Bangor, testified. She is the sister of Nicolle Lugdon and was living with Borders.

The Rhode Island man also said that he and Daluz left Carolina’s at about 11 p.m. on Aug. 12, 2012, and went to 15 Bolling Drive in Bangor to pick up the victims. The plan, Sexton said, was to sell Borders some cocaine and to smoke marijuana. Sexton said he was driving with Borders in the passenger seat. Daluz was behind Borders and Tuscano was behind the driver’s seat, with Lugdon in between them, Sexton testified.

“Nikki was talking about coming back to the hotel with me later,” Sexton said. “Dan was up front rolling a joint, when, all of a sudden this commotion breaks out. Dan says something to Daluz and Daluz gets pissed and smacks Dan in the head. Dan spilled the dope all over the car.”

Sexton said he did not hear what Borders said but described it “as something smart.”

“Everybody tells them to chill out, and I turn around and I see Daluz has a gun in his hand,” he continued. “He hits [Borders] with it a few times. Nikki’s telling him to chill out and the gun goes off and everybody starts screaming and yelling.”

Sexton said he was telling Daluz to put the gun down when his co-defendant shot Tuscano. That shot “blew out” the back passenger window. Lugdon became hysterical, he said.

Daluz ordered Sexton to keep driving but he was worried they were going to run out of gas, Sexton testified. Sexton said he turned around in Orono, then went to Dedham on Daluz’s instructions. There, Sexton put gas in the car, then put the gas can in the vehicle.

Sexton said that he drove to Hermon and down a dirt road where Daluz instructed Lugdon to swallow a number of pills. Daluz took money from Tuscano and Borders and gathered up shell casings, Sexton testified.

“He came to the driver’s side of the car and I got out,” Sexton said. “I got out and he asked if I was going to tell on him and I said, ‘No.’ He pointed the gun at me and raised his hand to the other window and, boom, he shoots Nicole.”

Sexton said that Daluz threatened to kill his children if he went to police so he agreed to burn the car with the bodies in it. Sexton said that he selected the Target Industrial Circle location because it was close to the Ramada Inn, but had to return there to get a lighter from Daluz, after he had dropped him off there, so he could start the fire.

Assistant Attorney General Lisa Marchese, who has a reputation for being tough on defendants during cross-examinations, will begin questioning Daluz as soon as jurors return from a lunch break around 1 p.m.

Daluz’s attorney Jeffrey Silverstein of Bangor will question Sexton after Marchese.