The call came in as a domestic disturbance -- a mother arguing with her son. When it was over, three Pittsburgh police officers were dead, the message that the son was armed never relayed by 911 dispatchers.
"We're walking into a blind situation," Pittsburg Police Officer Tim McManaway, who was shot but survived, told "Good Morning America." "How we're going to react is with that information we have."
When Margaret Poplawski called 911 on Saturday morning, she warned dispatchers that her son, 23-year-old Richard Poplawski was heavily armed, but that message never made it to the officers who responded to the scene.
"I can't apologize enough," Allegheny County Emergency Services Chief Bob Full said later. "But we can admit there was an error made."
Poplawski and his mother had been arguing over a urinating dog. His mother wanted her son out of the house they shared, but he had no plans of going quietly.
When police got to the house, Poplawski, wearing full body armor, including a bulletproof vest, was laying in wait with an AK-47 assault rifle.
Officers Paul Sciullo II, 37, and Stephen Mayhle, 29, were ambushed -- shot in the head and killed instantly. Officer Eric Kelly was hit in the arm and back.
McManaway has been hailed as a hero, rushing to Kelly's side despite being wounded by gunfire himself.
"He raised his arm, so I knew that he was alive," McManaway said of his friend.
A bullet had ripped into McManaway's left hand, but he managed to pull Kelly behind a car to shield him from the gunman. It was too late though.
"He wanted me to give a message to his wife and kids," McManaway told "Good Morning America." "I told him I wouldn't deliver the message, he'd have to do it himself."
Kelly, 41, died a short time later.
"The injuries went way beyond anything I could have done to get him to stick around," McManaway said, choking up.
After a four-hour standoff, Poplawski, shot by officers in the leg, surrendered and was taken into custody. A fifth officer broke his leg on a nearby fence and Poplawski's mother escaped unharmed after staying holed up in the basement during the incident.
Gunman Upset Over Job Loss, Feared Gun Ban
Police Chief Nate Harper said shortly after the shooting that while Poplawski's motive for the devastating murders was unclear, he had been upset about recently losing a job.
His close friend told ABC News earlier this week that Poplawski had long feared losing his right to own guns.
"They were all legal," his friend Edward Perkovic said of the weapons. "He had about four guns. I've been in houses where they have gun cases with 20 guns. He had a small, small amount of guns."
Internet postings by Poplowski on a white supremacist Web site, Stormfront.org, indicated he feared that President Obama would overturn the Second Amendment and he wrote that he believed Jews controlled the news media.
The officers who died were the first to be killed in the line of duty in Pittsburgh in 18 years.
"We wish that it would have been more black and white," Full said, "that the officers would have at least been given notice that there were weapons in the house."
The shootings of the Pittsburgh officers came two weeks after four police officers in Oakland, Calif., were gunned down.
The Associated Press contributed to this story.