Authorities found no signs that an office manager from Oak Ridge and the man who shot her down in October—minutes before being killed himself in a confrontation with police—had been in contact before the shooting, Morris County Prosecutor Robert A. Bianchi said.

What's more, a grand jury found police were justified in killing Leonardo Parera of Kearny, the prosecutor said in a press conference Thursday to announce the investigation into the matter is closed.

"The actions of these officers were nothing short of heroic," Binachi said. "They put their lives at risk and showed tremendous restraint and appropriate force to neutralize a man who was intent on engaging the police in a gun battle."

But what remains in question—why Parera would open fire on an innocent coworker, and then create a situation in which he'd almost surely be killed himself.

"I can't speak to what his motivation was," Bianchi said. "In this case, it really is a case of what you see is what you get. We don't know why he did it."

The account given by Bianchi Thursday of Oak Ridge resident Christine King's death and that of shooter Parera largely mirrors accounts given shortly after the Oct. 14 incident.

Authorities believe King and Parera, coworkers at Exit Gold Realty in Mountain Lakes, had both been to work that day. Bianchi said Parera entered the office and fired 15 shots at King with a 9mm pistol, killing her instantly. Newly revealed is that an autopsy indicated she'd been shot from behind.

Binachi said another person was inside the business and called 911, but had no contact with Parera.

Parera moved his car to the back portion of an adjacent parking lot, for the Villa at Mountain Lakes, a catering Hall, Bianchi said. Parera called police from the car, both urging officers to come and warning them that if any approached, he'd open fire.

"We're not going to de-escalate this. I'm looking to escalate," Parera could be heard saying in an audio recording of the call released by authorities last year.

He also told a dispatcher he expected to die soon, and wanted to call some people first. Binachi said Thursday he called both his mother and his sister after the 911 call ended.

When officers arrived, they and Parera exchanged gunfire, ultimately killing Parera, Bianchi said.

According to the prosecutor's statement Thursday, ballistics analysis showed Parera fired at least eight shots at police; one shot hit a building at 100 Route 46. Bianchi said officers ordered him to surrender, but those instructions were ignored. Bianchi also said civilian witnesses saw Parera firing from his car.

Parera was shot 11 times over 23 seconds, Bianchi said. About 65 shots in total were fired by police; 53 of those hit the car, he said.

Several police agencies had been involved in the response. Initially, the  Mountain Lakes, Parsippany and Denville Police Departments responded. They were soon joined by the Morris County Prosecutor’s Office Tactical Team along with the Morris County Sheriff’s Office Emergency Response Team.

Authorities conducts an extensive forensic examination of King's computer and phone records, as well as of Parera's computer, and none of those records suggested any contact between the two, Bianchi said.

Bianchi said the investigation also showed the shots from Parera's gun were King's sole cause of death, and that he conducted the homicide alone.

"My prayers and sympathies to Ms. King’s family, as well as the police officers involved," Binachi said. "No officer, even when use of force is justified as is the case here, enjoys being responsible for taking another person’s life.  These officers were compelled to use deadly force for the protection of themselves, as well as the citizenry who were present in a well populated area. Simply put, the police response was textbook and exhibited great skill and training in the face of lethal force being employed against them.”

King was remembered by loved ones in an obituary last year as a woman who "enjoyed life and loved to entertain." The 47-year-old Oak Ridge resident was married and had two sons.