DUBLIN (CBS SF) — The powerful drug fentanyl was found near two janitors discovered unresponsive inside a Dublin middle school library after being reported missing, Dublin police said Thursday.

One of the two janitors, 32-year-old James Covington of Pittsburg, died at the scene. His co-worker and fiancée, 29-year-old Shameka Wilbon, was hospitalized and will survive.

But Covington’s family doesn’t believe drugs were involved. They think a new chemical that was used to spray down Fallon MIddle School and eliminate the COVID-19 virus caused the death.

“(The chemical) made them sick, maybe there wasn’t enough ventilation. They don’t have respirators,” said Covington’s mother, Tamara Covington-White.

Dublin police tracked their cell phone signal and found the two janitors unresponsive in the library Wednesday morning. Covington-White saw Dublin police pull her son’s lifeless body out from the school’s library. She came back to the school Thursday afternoon with flowers and balloons to remember him.

“We’re not going to let him die in vain,” said Covington-White. “He was too good of a kid for that. And I’ll never stop fighting for my son, ever.”

She filed a missing person’s report Tuesday night after Covington and Wilbon didn’t come home from work at the school. Very few staff members were on campus because of the Christmas break.

Family members said the two Dublin Unified School District employees were raising two children together, 10 and 12 years old.

“They don’t want to celebrate Christmas,” cried Covington-White. “They want to send all their gifts back. And they want their daddy back. There’s no miracle for that.”

“The only thing that we worry about now is the kids,” said Covington’s stepfather Sedric White Sr. “They’re taking it very hard. Christmas will never be the same for them right now.”

Dublin police said they smelled a strong chemical in the library.  By the time the hazmat team arrived, the odor had dissipated. Police said they found fentanyl near the two custodians. They’re waiting for the autopsy and toxicology reports to find out what killed Covington.

Dublin Police Captain Nate Schmidt said it’s very unusual to have someone going missing and dying in a school.

“I’ve been working in police work for about 22 years,” said Schmidt. “And this is the first type of incident that I’ve seen that’s even similar to this.”

Police said they are seeing a sharp rise in fentanyl overdoses across the country.

“That’s a lie and I’m not going to let them drag my son’s name in the mud,” said Covington-White.  She said her son didn’t do drugs and had been telling others to stop using drugs.

Dublin police did not suspect foul play and they did not anticipate any criminal charges to be filed against the surviving Wilbon. They said it was a tragic incident and they feel for the family the two kids.