A pregnant nanny was killed when she was struck in the chest by a stray bullet during a family outing in the Arizona desert.

Kami Gilstrap, 24, was visiting an area popular for target shooting and ATV riding Sunday when she was hit — and the person who fired may not even know they killed her, investigators said.

“It is believed that the person involved may not know that they shot someone,” said Buckeye Police Department detective Tamela Skaggs on Tuesday.

“This does raise concerns, however, with reckless shooters in this area who are not aware of what their backdrop is when shooting.”

Friends said Gilstrap, an Oklahoma native, was married to an airman stationed at Luke Air Force Base and that they were expecting their first child. According to her Facebook, she worked as a nanny for a local family with a baby girl.

“I can’t believe she is in heaven now. We will miss her so much it hurts,” wrote Ann Bussert Hall, Gilstrap’s aunt and a missionary in Cambodia.

Witnesses told cops they heard three shots and that Gilstrap was hit by one of the bullets.

Cops said the area north of Interstate 10 and Miller Road is a popular place for people to shoot recreationally.

But the government-owned swath of land is full of garbage, which creates the potential for dangerous ricochet.

“Out here we have tons of trash. All that trash is potential for a round to ricochet and hit another shooter,” Buckeye Police Chief Larry Hall told AZ Family. “And that’s where this whole situation out here is absolutely dangerous. I would never bring my family out here and I’d never bring my friends out here.”

Police said that hundreds of shooters were out on that day, which would make finding the person who fired the bullet extremely challenging.

As of Tuesday, Skaggs said there were no suspects but that the investigation was ongoing.

“Persons shooting in legal areas must be responsible for where their bullets are going,” she said.

Additional reporting by Joshua Rhett Miller