Police arrested a Baton Rouge man Thursday and are trying to determine whether a second person was involved in a fatal shooting Monday night in Port Allen, Chief Esdron Brown said Thursday.

Police arrested Javonte T. Morgan, 19, on counts of first-degree murder, attempted first-degree murder and armed robbery, Brown said.

Police believe Major Carter, 30, and Ashton Taylor, 25, both of Baton Rouge, went to the 300 block of Tracy Porter Street on Monday night to buy drugs. But, instead, Morgan tried to rob the two men, Brown said.

Carter was shot in the back and later died from his injury, Brown said. Taylor was shot in the buttocks.

The investigation is ongoing as police try to determine whether another person was with Morgan during the incident, Brown said.