When Louis Agro opened the door from his Wilton Manors home to his garage early Monday, he collapsed and died — overcome by carbon monoxide fumes from his SUV, which had been left running for six hours, detectives said.

Agro did, however, manage to flip a switch on the wall, opening the main garage door — a final act that may have helped save the lives of his wife, daughter and neighbors.

"We don't know if he heard something, felt something," said Broward Sheriff's spokeswoman Gina Carter. "Something told him to go down there in the middle of the night and he did, but it was too late."

The family's 2015 gray Ford Escape would remain running with the key in the ignition for another six hours before neighbors discovered something was terribly wrong and alerted authorities, she said.

"The car was still running the next morning," Carter said. "He never made it to turn off the car."

Broward Sheriff's detectives and the medical examiner's office have concluded that carbon monoxide poisoning caused the accidental death of Agro, 43.

His body was found by neighbors Keith Moore and Mark Thompson just before 8 a.m. Monday on the floor of his home in the 2200 block of Northeast Ninth Avenue in the Belle Isle neighborhood.

They performed CPR in vain until Fort Lauderdale Fire Rescue arrived to find Agro's wife, Regina, 37, and their daughter Sophia, 11, overcome by the fumes inside their home.

Regina Agro remained at Mercy Hospital Miami and Sophia Agro was at Broward Health Medical Center on Tuesday. Their conditions were not available, Carter said.

Moore and neighbors Kyle White and Michael Gutierrez were also sickened by the toxic gas. All were taken to the hospital in critical condition, investigators said Monday.

"[White and Gutierrez] woke up to the sound of some commotion [but] they didn't really know what it was because it was early in the morning," Carter said. "They didn't think much of it and stayed in bed until fire rescue came and got them out of there."

Keith Seidon, president of the Belle Isle neighborhood board, said he spoke with White via text message Monday night, and White said he and Gutierrez "were doing OK."

White and Gutierrez have been renting a townhouse in Belle Isle for about a year, Seidon, 57, said.

He said if it weren't for Thompson and Moore's decision to step in, more lives, including those of White and Gutierrez, could have been lost to the lethal gas.

"They were definitely heroes yesterday," Seidon said. "Without them, who knows, the car could still be running."

On Tuesday evening, Thompson said Moore was home resting, but declined to comment on the previous morning's events.

Hector Rodriguez, 35, was returning from work at about 8 a.m. Monday when he saw his 11-year-old neighbor unconscious in the driveway of her family's home. He said fire trucks and ambulances surrounded the motionless girl as she was given oxygen by rescue crews.

"It's shocking," said Rodriguez, who met the Agro family four years ago when he moved into the neighborhood. Rodriguez and Louis Agro would chat regularly and bonded over the fact that they both hailed from New York, he said.

"He was a very nice guy," Rodriguez said. "It's a shame."

Agro was often in his driveway washing his vehicles, Rodriguez said.

"They were always out and about," he said of the Agros. "They would have cookouts in their driveway."

The Agro family had returned to their Wilton Manors townhome about 8:30 p.m. Sunday from a trip up north to a property where they had planned to build a home, Carter said.

Detectives have not been able to talk to the mother and daughter about what happened, she said.

From our media partner Sun Sentinel