CLEVELAND, Ohio — The number of police officers dedicated to investigating homicides in the city has dwindled to 13, nearly half the number promised by city officials in the wake of an expert’s determination that the city’s low rate of solving homicides is tied to understaffing.

There are currently 15 detectives assigned to the unit, but two aren’t working — one due to medical issues and another who is awaiting discipline after pleading guilty to disorderly conduct in a fight with a family member.

The small staff comes as the city had one of the most violent months in recent years. Twenty people were killed in in September, the deadliest month in the city since 21 people were killed in October 2016, according to medical examiner and police records.

Cleveland Police Chief Calvin Williams declined to be interviewed for the story. In a statement, the department said it intends to add a “limited number” of detectives are expected to the unit in coming weeks. The statement provided no details on when that would happen nor why the department continues to keep it understaffed.

Williams told City Council in March that he expected to have 23 homicide detectives in the unit by the end of the year. He had 14 detectives at the time.

Williams made the promise after an income tax increase approved by voters in 2016 gave the city enough money to increase the amount of police officers in the city.

Cleveland officials in 2017 negotiated with the police union to give Williams power to appoint two detectives to the homicide unit for every one that’s added based on seniority. Previously it had been a one-for-one exchange. Williams has appointed only two detectives in February and a third was added by seniority.

Williams previously told council that he wanted to get the total number of police officers up to about 1,600 before filling out the specialized units. The city reached that number with a new class of police officers sworn in on Sept. 20.

The city is inching toward 100 homicides for the ninth consecutive year. There have been 97 homicides in the city so far in 2019, according to medical examiner and police records compiled by cleveland.com.

The police department has solved about half of homicides since 2016. In 2018, the department solved 50.4 percent, well below the national average of 62.3 percent reported by the FBI in 2018.

City officials have not responded to a cleveland.com records request for the solve-rate for homicides thus far in 2019. A quadruple homicide in September and the slaying of a 6-year-old girl in early October remain unsolved.

Staffing within the homicide department drew criticism in a 2016 report by the Washington D.C.-based Police Executive Research Forum which noted that in 2012 the department had 19 detectives and solved 77 of 100 homicides.

The number of detectives dropped to 14 in 2017, despite topping 100 homicides in each of the years since 2012.

The research group recommended 75 changes the department could make to help better solve and investigate homicides.