A spike in suicides at a California women’s prison has prompted officials to increase oversight and start an inquiry into potential reasons for the increase, the Associated Press reported. The California Institution for Women in San Bernardino County has reported four suicides in the last 18 months, state records indicate. That suicide rate is more than eight times the national average for female inmates and more than five times the average for the entire prison system in California. There have also been 20 attempted suicide attempts among the prison’s population of 2,000 during the same period.

The Institution for Women is also the only prison in California to  have had any suicides in the last five years. And before the spate of new incidents, there had been only three suicides at the prison over a period of 13 years.

The scrutiny comes at a time when national attention is focused on Sandra Bland, the black woman who was stopped for a traffic violation in July and was found hanging in a Texas women’s prison shortly after. Her death is viewed as suspicious by family members and others.

The Institution for Women’s recent suicide rate has surprised some as the facility was often touted as an institution that offered proper mental health treatment for inmates. The four prisoners who committed suicide had all been receiving mental health care at the facility.

A court-appointed suicide expert called the prison "a problematic institution that exhibited numerous poor practices in the area of suicide prevention."

Suicide in California prisons has long been a problem among the male inmate population, but the prevalence among the female population is a cause for concern, experts said. As a result, inspectors will be looking into all suicide attempts to “pinpoint what’s going on ... since it seems to be spiking there,” spokesman Shaun Spillane told the AP.