The former employee was arrested earlier this month after Concord police said investigators found evidence supporting allegations that she had engaged in a sexual relationship with a 17-year-old. ABC7 Eyewitness News is not naming the former employee, who is a San Francisco resident.
Charges involving child sex abuse have been filed, the District Attorney's Office said Monday.
The former employee is facing seven felony charges for alleged unlawful intercourse with a minor, sending harmful matter to a minor, being in possession of child or youth pornography, and other counts of sex abuse involving a minor, prosecutors said.
The teenager is identified in the claim only as John Doe because he is a minor. ABC7 Eyewitness News is also not naming his parents to protect his identity.
MORE: Former San Francisco deputy charged in alleged jail sexual assault case, authorities say
Attorneys say the teenager was in custody at John A. Davis Juvenile Hall in Martinez when Contra Costa County assigned the temporary health worker to counsel him in 2024. He was 14 and she was 24.
"We had conversations about where he was mentally, and we trusted her," the teenager's mother said.
The claim alleges the counselor crossed professional boundaries and drew the teenager into increasingly personal and romantic conversations while he remained in custody.
"This woman used my child's most vulnerable moments to groom and make him believe she was his girlfriend," his mother said.
The teenager was released from juvenile hall in April but remained 17 years old and under the supervision of the Contra Costa County Probation Department, according to the claim.
Attorneys allege the former employee continued seeing him under the guise of therapy and then began having sexual contact with him.
Civil rights attorney John Burris, who is representing the family, said the counselor exploited the teenager she had been assigned to help.
"The reason he was there was having emotional and mental problems, and her job was to help solve those problems, to rehabilitate him, to teach him and understand that, and she did just the opposite," Burris said.
Concord police said they began investigating after receiving a tip from the county Probation Department. Police later arrested the former employee after finding evidence supporting the allegations. She was arrested earlier this month.
MORE: Los Gatos mom sentenced to nearly 36 years for hosting drunken teen sex parties: 'I am ashamed'
Police said after the arrest that no additional alleged victims had been identified.
The claim, which is required before the family can file a lawsuit against the county, also accuses county and state workers of failing to recognize or report repeated warning signs.
"Accountability for every supervisor who is a mandated reporter who missed years of shades of red flags," attorney Katherine MacElhiney said.
Andrea Harner, a board member with the national nonprofit Darkness 2 Light, said mandated reporter training alone does not adequately prevent abuse. Harner said youth-serving institutions need specialized training focused on preventing abuse and identifying grooming before misconduct is reported.
"How to minimize opportunity, how to report responsibly, how to recognize signs of grooming. Because the whole thing is that a lot of these perpetrators will go into professions where they're not only with kids but with vulnerable kids," Harner said.
Advocates say such cases can go unreported because children may not recognize that they are being groomed or may fear they will not be believed.
The teenager's mother urged other parents not to dismiss their concerns.
"Trust your instinct. Something told me something was off, but I dismissed it because I couldn't believe that a professional in her capacity could do what she did," she said.
RESOURCES: Get help with violence, assault and abuse at home
Contra Costa Health said it is aware of the claim involving a former temporary employee and allegations involving a minor.
"Because this is an active legal and personnel matter, Contra Costa Health cannot provide additional comment at this time," the department said.
Attorneys representing the family said they are working to determine whether there may be other alleged victims.
Bay City News contributed to this story.