Kansas City, Mo. ? A mother accused of giving her 4-year-old son crack cocaine to “calm him down” has been charged with first-degree endangering the welfare of a child.

Michelle R. Shelton, 32, of Kansas City, was arrested Thursday and was being held on $25,000 in bond.

Assistant Prosecutor Peter Gromowsky said the case was unusual because of the amount of the drug found in the child’s system.

“But the sad truth is,” he said, “this is fairly common for kids to be exposed to drugs.”

Police said the child remains in state custody.

Police first began investigating Shelton a year ago when officers say they saw her escorting drug users into the apartment complex where she and her son lived. Police said some residents at the complex told investigators Shelton sometimes gave the boy crack cocaine to “calm him down.”

Social workers were sent to the apartment where they took hair samples from Shelton and her son to test for illegal drugs. The tests came back positive in April, police said.

According to court records, Shelton told detectives she found empty crack bags and drug paraphernalia throughout her home after parties her son attended. She said it was possible the child found some of the drug.