A crazed teen gunned down a 15-year-old boy and a hero mom of eight just for being turned down from joining a casual game of soccer, according to cops.

Rafael Martinez-Lopez, 18, allegedly pulled out a gun and shot young teen Jeremiah Griffin-Cuevas in a fight over the game at an elementary school in Grand Rapids, Michigan — then also killed mom Savanah Villarreal, 39, when she tried to help.

“She gave her life to save my son,” Griffin-Cuevas’ mom, Mildred Griffin, told Fox 17 through tears.

The suspected killer was busted at home after fleeing the bloodbath — which was witnessed by at least eight horrified kids, cops said.

“A bunch of kids were playing at the park here, and the suspect approached, asked to engage in a game of soccer,” Grand Rapids Interim Police Chief Joe Trigg told WOOD-TV. “For whatever reason, he was turned away.”

He “did not like the fact that he was turned away so a verbal altercation started, which led to the suspect pulling out a firearm and shooting” the 15-year-old boy and then Villarreal, who was supervising the game, Trigg said.

Griffin-Cuevas died at the scene Tuesday and Villarreal later succumbed to her injuries at a local hospital. No other injuries reported but as many as eight other kids witnessed the killings, police said.

Villarreal had been supervising the game “because there’s been several incidents here where they have been verbally attacked and things,” her sister, Angelita Tierrablanca, told WWMT. “She was so selfless, she loved children.”

Villarreal was also like family to the boy murdered alongside her, his mom said.

“He considered Savanah his auntie,” Mildred Griffin told Fox 17. “She’s been in his life his whole life. She was his babysitter.”

Family and friends said Villarreal was well-known in the community for her work with a local nonprofit distributing groceries and household items to families in need.

“She guarded Jeremiah in her last moment. She played her role exactly as she was supposed to as a mother and a guardian,” a friend, Alana Crooks, told Wood-TV.

“Savanah and Jeremiah should not be dead right now. They shouldn’t.”

Classes were canceled at Southwest Elementary School until Friday as police investigated the scene.

Martinez-Lopez is facing two counts of open murder, two felony firearm charges, and three additional weapons charges.