The twins were slumped in the front seats, exhaust pouring into the driver’s-side window through a garden hose duct-taped to the tailpipe. It was their 31st birthday.

Shawnee Police Officer Nick Shurmantine believes both men would have been dead in minutes had he not come across their car.

“I think I was their guardian angel (Tuesday) night,” Shurmantine said.

On Wednesday, Shurmantine told reporters he was glad he interrupted the men’s suicide attempt — as a police officer, he said, it’s his job to protect life. But he was left wondering why they did what they did.

“That’s the question I want answered more than anything,” he said. “But I don’t think I’ll ever know.”

Shurmantine, a three-year veteran of the police department, was nearing the end of his shift Tuesday night when he decided to make one last pass through a neighborhood where copper thieves have been targeting partially constructed homes.

About 9:15 p.m. he spotted the car running in the driveway of an unfinished home in the 6100 block of Clearcreek Parkway.

Shurmantine’s first guess was thieves. But he didn’t see movement on the property or flashlights in the house, he wrote in his report. As he got closer to the car he noticed the garden hose, then shined his light inside and saw the unconscious men.

“It went from being ‘I’m going to catch some criminals in the act’ to saving someone,” Shurmantine said. “It’s an instant switch.”

Shurmantine, who said he spent five years as an emergency medical technician before becoming a police officer, pulled open the driver’s-side door to let in fresh air and checked the men’s carotid arteries for pulses. Both were very weak.

He shook the men and yelled at them before one gasped for air. Both were talking but confused before they left for the hospital, Shurmantine said.

There was no note or anything else explaining their actions on the men or in the car.

Suicide pacts are rare but real, Shawnee police spokesman Capt. Dan Tennis said. He said that he’d heard of more cases — though none in Shawnee — involving teens than adults and that, often, those were successful.

Tennis said it would probably be up to the men’s mental health professionals to decide whether they would talk to Shurmantine. As suicide is not illegal, Tennis said, police would not interview the men, who are Olathe residents, as they would in a criminal investigation.

Shurmantine said he would speak with the men if given the chance.

“I would love to sit down and talk to them and try to get some answers for myself,” he said. “It’s a lot to soak in.”