Authorities say the male suspect exited the residence and engaged police just after 9:15 a.m. The suspect was then shot by law enforcement and was pronounced dead at the scene at 9:29 a.m.
A news conference will be held at Delaware State Police Troop 2, Glasgow at 1:30 p.m., where more details of this investigation will be discussed.
Residents in the area remain evacuated, and the Odessa Fire Company has opened its facility to temporarily house the evacuated residents of Brick Mill Farms Development.
There were reports of gunfire throughout the night, with residents in the neighborhood reporting what they described as loud blasts.
Resident near standoff: "Some of them are bad, about 4 or 5 have been massive explosions." @6abc— Jeannette Reyes (@6abcJeannette) April 27, 2017
Cpl. Stephen J. Ballard was shot around noon Wednesday at the Wawa on Pulaski Highway (Route 40) near Salem Church Road. He later succumbed to his wounds.
Ballard, 32, was an eight-year veteran of the Delaware State Police and was assigned to patrol at Troop 2.
The suspect's name has not been released.
"This is a sad day for our state and our Delaware State Police family," Delaware State Police Superintendent Nathaniel McQueen said. "We ask that you keep the trooper's family, and the Delaware State Police family, in your thoughts and prayers."
A caravan of law enforcement vehicles accompanied the slain officer's body to the state Division of Forensic Services for an autopsy, and observers placed their hands over their hearts as it passed by.
VIDEO: Police escort for fallen Del. trooper
Delaware Gov. John Carney is offering his condolences to the relatives and colleagues of a slain state trooper. In a statement, he said his "heart is with the officer's family and the officers who have served beside him."
Carney said "officers go to work every day knowing they put their lives on the line to protect ours," and that Delawareans are "incredibly indebted to their bravery and service."
Wawa officials released a statement Wednesday night saying, "We are deeply saddened by the tragic situation that occurred in the parking lot of our Bear, Delaware store today. Our hearts are broken and our thoughts and prayers are with the officer's family and the entire Delaware State Police community during this difficult time."
The statement notes that the store will remain closed until Saturday "out of respect to the officer, our associates and all those affected."