AUBURN — When Auburn police Officer Ronald Tarentino Jr. ran the plates attached to an SUV driving along Rochdale Street early Sunday morning, he quickly realized something was wrong: Records showed the plates belonged to a Nissan Maxima, not the Infinity SUV in front of him.

What unfolded from that moment was a police officer’s nightmare: a routine traffic stop that quickly turned deadly. The driver shot and killed Tarentino and sped away, sending dozens of local law enforcement on a frantic 18-hour search for the killer.

Details of the shooting timeline emerged Monday.

Edward Lemieux and his family, who live on the corner of Rochdale and Caroline streets, were heading to bed around 12:30 a.m. when they heard what they thought were fireworks. After the fourth pop, he said, they realized someone had been shot.

He and his wife peered out the window and saw Tarentino lying beside his cruiser, Lemieux said.

Tarentino cried out for help.

“Everything is going to be all right,’’ the Lemieuxs told Tarentino. “Everything is going to be OK.’’

But it wasn’t. Tarentino, 42, a married father of three, was pronounced dead at the University of Massachusetts Memorial Medical Center.

By mid-morning, police had information that led Auburn officers and the State Police Special Tactical Operations Team to 31 Watch St., a duplex in Oxford about five miles away.

Police believed that Jorge Zambrano, a 35-year-old with a long criminal history, was inside and that he was the man who killed Tarentino more than 10 hours earlier.

Zambrano’s name had emerged as a possible suspect when the State Police realized that they had stopped the same vehicle, with the same attached plate, a week earlier in Worcester and had arrested Zambrano.

Pete Bailey, who lives across from the Watch Street duplex, said he watched as a negotiator spent hours trying to encourage Zambrano to surrender. The negotiator asked Zambrano to call officers and to wave a curtain to let them know he was there, said Bailey, 47.

Using a long-range acoustical device, the negotiator told Zambrano that investigators had spoken with his brother in Florida, who was planning to get on a plane, and that his daughter was worried about him, Bailey recounted.

But Zambrano never responded, according to Bailey.

In the meantime, armed officers had flooded the area, taking cover behind bushes and trees.

At 2 p.m., the tactical team ordered everyone out of both sides of the duplex, according to State Police spokesman David Procopio.

Moments later, a resident of the duplex emerged and told police that Zambrano was inside, was armed, and did not intend to surrender peacefully, Procopio said.

Officers fired tear gas into the building and used a robot equipped with a camera to search the residence, but it did not capture any images of a person inside the building.

Officers and police dogs entered and searched the building floor by floor, finding a hole the size of a pizza box in a cellar wall between the two sides of the duplex. That led police to search the other side of the duplex as well.

During that search, three State Police troopers came across a closed closet in a small second-floor bedroom. When troopers opened the closet door, a pit bull ran out, past the troopers, and out of the room. Seconds later, a hand holding a gun reached out from behind some clothing and fired at the troopers, according to Procopio.

A bullet struck one of the troopers. The others returned fire and Zambrano was killed.

The injured trooper, an 18-year veteran who was not identified, had surgery Sunday and was recovering Monday, Procopio said.

Worcester District Attorney Joseph D. Early Jr. is investigating Tarentino’s death and the use of deadly force by state troopers against Zambrano.

Auburn Police Sergeant Scott Mills, who described for the Globe Tarentino’s initial realization that the car he stopped early Sunday was not displaying the proper plates, also said that Auburn police vehicles are not equipped with dashcams and there were no surveillance cameras in the area.

Tarentino, a two-year veteran of the Auburn Police Department, had previously worked with the Leicester Police Department for seven years.

Officers from both departments said they were heartbroken.

“Ronny is that kind of guy . . . [who] makes friends with everybody,’’ said an emotional Leicester Police Sergeant Paul Doray, who described Tarentino as one of his best friends. “A lot of times police officers can get withdrawn from the community, but this was not the case with Ronny.’’

Leicester Police Chief James J. Hurley said Tarentino’s “career track was to move forward.’’

“Tarentino’s tragic death prevented a violent crime from occurring to someone else and that is what Ron was all about, helping others,’’ Hurley said.

He had always aspired to become a police officer like his father, who worked in Medford, according to those who knew him. Mills said Tarentino wanted to become a detective.

Throughout the day Monday, people poured into the Auburn police station, placing flowers at a growing memorial and bringing food for the officers.

“It’s a tough day for the town,’’ said a teary-eyed Judi Laplante, 55, who came to the station with her daughter, Brooke, 13, and son, Luke, 14, and doughnuts and coffee.

John Peduzzi wept quietly as he knelt down in front of the memorial. He said he had lost his best friend.

Peduzzi described Tarentino as a Mustang aficionado, who belong to a club that traveled to car shows and cruised through the town on Friday nights. The two also went hunting and fishing together, he said. They were planning to go deep-sea fishing in two weeks.

In Tewksbury, where Tarentino’s parents lived, Pat Paquette wound black and blue ribbon around a tree in her yard.

It was a simple gesture, she said, to honor the loss of a man she had watched grow into an adult only to be cut down while doing the job he loved.

“It’s just so sad that somebody with so much ahead . . . has been taken away so tragically,’’ she said. “And for what?’’

Tarentino’s funeral is scheduled for 11 a.m. Friday at St. Joseph’s Catholic Church in Charlton. A wake is scheduled for 2 p.m. Thursday at the church.

Andy Rosen, Astead W. Herndon, Shelley Murphy, and John R. Ellement of the Globe staff contributed to this report. Jan Ransom can be reached at jan.ransom@globe.com.