A television station’s investigative team asserted Monday that nursing home sexual abuse incidents in Texas are not thoroughly investigated, and that state officials may not be doing enough to protect victims.

The report, by ABC affiliate KVUE in Austin, uncovered nearly 500 sexual abuse cases in Texas nursing homes since 2009. Of that number, state investigators determined only eight to be legitimate, the report alleges. Researchers also say scores of other cases have been closed without a thorough review of evidence.

Texas Department of Aging and Disability Services Commissioner Jon Weizenbaum told reporters the agency’s efforts to gather evidence is often stymied by victims who are unable to speak for themselves.

Accurate data on the prevalence of nursing home sexual abuse is difficult to ascertain. The National Center on Elder Abuse estimates as many as 53% of adult women with disabilities may experience sexual abuse.