Montgomery County Detective Mario Mastrangelo had Thursday mapped out: A planned trip to his office and the courthouse with his two youngest for take your kids to work day. But moments into their ride, Mastrangelo saw smoke billowing from a nearby house, and he drove straight to it.

“Stay in the car,” he told them.

Mastrangelo ran inside, found a woman in the kitchen and carried her out. The woman told him that her husband was upstairs. Mastrangelo went back in, aided by a neighbor with a garden hose. But the top of the stairs was walled off by flames. Smoke started to overcome them, and they were forced to make their way out of the house.

“I wish I could have gotten them both,” Mastrangelo said Thursday afternoon.

Fire officials did not release the names of either occupant of the home, a two-story structure on Jamieson Place, a cul-de-sac in Germantown.

Neighbors described the couple as friendly. “Very nice people,” said Melissa Johnson, who lives next door. “It’s very sad.”

On Thursday morning, Mastrangelo picked up his kids after they had spent the night with their mother. Max, 12, got in the front seat. Daniela, 9, was in the back.

The two had experienced scares with their dad before. Last year, he suffered a heart attack in his kitchen while making them pizza. The detective has since recovered, now with a stent in his chest, and returned to his job as a child-abuse and sexual-assault investigator. On Thursday, he planned, among other things, to show them a polygraph machine.

But he was quickly diverted by the smoke.

As the kids watched their dad run into the burning home, they grew frightened that he might not come out. Daniela started to tear up.

Inside, Mastrangelo made his way toward the back of the first floor.

“Can anyone hear me?! Is anyone here?!” he recalled yelling out.

In the kitchen, he saw the woman.

“I need my oxygen tank. I need my oxygen tank,” she said.

“We need to get out of the house,” Mastrangelo said, lifting her up and taking her out.

“Is there anyone else in the house?” he asked.

“My husband’s upstairs,” she said.

The neighbor, using the home’s garden hose, helped him try to get up the stairs. But there was fire on the ceiling and flames blocking the top of the stairs. “Knowing someone was there was killing me,” Mastrangelo said.

As they came back outside, fire crews were arriving at the house.

Firefighters then battled their way to the second floor and found the body of the man, 65.

Battalion Chief Dee Howard Richards, a spokeswoman for the county Fire and Rescue Service, said Thursday evening that the fire was thought to have started on the second floor but that the cause remains under investigation. She said the woman, 68, was taken to a hospital with injuries that were not considered to be life-threatening.

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