SEATTLE (AP) — Seattle Mayor Bruce Harrell says the police department’s low staffing in its sexual assault unit that has led to a backlog of dozens of stalled cases is “unacceptable.”

Harrell made his comments Thursday following a report by The Seattle Times and KUOW-FM of an internal memo that showed the unit stopped investigating most new sexual assault cases involving adults this year.

Harrell rejected the idea his administration did not prioritize sexual assault cases. But he said the current state of the unit –- and its backlog of 48 stalled cases that had not yet been investigated –- was “not where it needs to be.”

“I’m not happy with where the city is, but we will indeed make sure that we are providing optimal service, both for investigation and victim survivor support here this year,” Harrell said.

Harrell suggested recruiting retired detectives to investigate sex offenses, but said he was limited by labor agreements. He also committed to meeting within weeks with concerned victim advocates.

Increased staffing is ultimately needed across the police department, Harrell said.

Advocates for victims of sexual assaults have questioned whether the root cause was staffing, or the department and city leaders’ priorities.

Riddhi Mukhopadhyay, executive director of Seattle nonprofit Sexual Violence Law Center, said victim advocates said the memo “confirms what we’ve all been seeing.”

The police department’s “response has always been kind of slow and not as timely compared to other jurisdictions. But it’s gotten worse,” Mukhopadhyay said.

The police memo published by The Seattle Times and KUOW-FM was written by the Seattle police sexual assault and child abuse unit’s Sgt. Pamela St. John and sent in April to interim chief Adrian Diaz this April, the two media outlets reported.

The memo stated that the sexual assault and child abuse unit was so understaffed it had a backlog of stalled sexual assault case and that four detectives remained were in the unit earlier this year, as opposed to 10 to 12 detectives earlier.

The unit has since added an additional detective and plans to add another one this month.

But the understaffing means that fewer sex assault cases are referred to prosecutors, prosecutors and advocates told the news outlets.