SAN ANTONIO -- The family of a San Antonio teen confirms it is filing a lawsuit against a northwest-side treatment center, just days after a former counselor there was arrested on multiple charges of sexual assault.

Alexander Williams, 25, was arrested late Monday night, more than seven months after San Antonio Police began investigating him.

Williams has been placed on administrative leave from his job as a residential treatment officer for the Bexar County Juvenile Probation Department.

The two-count indictment of Williams concerns his tenure as a counselor at Laurel Ridge's Highpoint Center facility, a center that bills itself as a "formative years day treatment program."

According to the victim's father, who reached out to the KENS 5 I-Team earlier this week, Williams' position as a counselor gave him access to the teen's medical history. The history included a diagnosis the teen was "high-risk for sexual activity."

KENS 5 is not naming the teen or her family to protect her identity.

Her father said the sexual relationship between the teen and Williams started within days of her beginning outpatient treatment. 

The father told the I-Team via telephone that he contacted Laurel Ridge on May 4, 2015. The center immediately suspended Williams, then filed reports with SAPD and the Texas Department of Family Protective Services.

Williams resigned his position days after the investigation started, the teen's father said.

Laurel Ridge officials did not respond to multiple requests for comment on this story.

The family's attorney, Edgardo Baez, said his firm will file a lawsuit against Laurel Ridge in state district court as early as next week.

Despite being under investigation by SAPD, Williams was able to interview in June and then land a job in July supervising children as a residential treatment officer for the Bexar County Juvenile Probation Department.

"Obviously, we would not have hired him if we'd known there were pending charges or an incident that had happened," Chief Juvenile Probation Officer Lynne Wilkerson said.

Wilkerson said an internal investigation after Williams' arrest revealed he did not list his work for Laurel Ridge on his county application. Wilkerson said her department continues to look into other possible discrepancies on his resume.

Wilkerson said there had been no allegations of misconduct against Williams during his five months with the department. He was assigned to a boys unit within a county juvenile detention facility.

Williams remains at the Bexar County Jail.