The distraught mother of Colorado shooting suspect Devon Erickson told The Post on Wednesday that she doesn’t know why her son opened fire on his classmates.

Stephanie Erickson, 56, whose son allegedly killed one and injured nine others with an accomplice during an afternoon shooting spree at a STEM school outside of Denver on Tuesday, said she wasn’t ready to talk about the incident yet.

“We just need a little time right now,” Erickson told The Post as she broke down in tears.

When asked if her son was bullied or if she had any idea why he’d commit such an atrocity, she answered: “I don’t, no,” then began to cry harder. “I’m sorry, I just can’t talk right now. Thank you.”

Devon Erickson, 18, will have his first court hearing Wednesday, when prosecutors will announce initial charges against him.

He’s expected to be slapped with 30 counts, including one count of first-degree murder after deliberation and 29 counts of attempted first-degree murder, according to the Denver Channel, which cited court records.

Devon Erickson acted in concert with another suspect, a minor who’s yet to be identified, police said. That person is not expected to be charged Wednesday, authorities said.

Cops initially called the second suspect a male but later changed the gender to female. Sources told the Denver Channel the suspect is transgender and is undergoing a female-to-male transition.