Since taking office in 2011, Mayor Rahm Emanuel has repeatedly vowed to deploy more police officers to combat violence in city neighborhoods, both by pulling them from desk jobs and hiring more recruits.

“I promised to put 1,000 more police officers on the streets where they’re needed, not behind desks in office buildings or in specialized units that don't get to know the communities they serve,” Emanuel said when he was running for re-election in 2015. “And that’s what we’ve done.”

As recently as last month, when he introduced his 2018 budget, the mayor repeated the pledge.

“This budget puts more police on our streets, and gets kids, guns and gangs off the street,” Emanuel said.

But even as the city spends tens of millions of taxpayer dollars on police overtime and hiring, hundreds of officers have taken desk jobs in the department over the last four years, according to records obtained by ProPublica Illinois. In one unit, the number of officers has more than quadrupled.

At the same time, hiring hasn’t kept pace with retirements and other departures, leaving the police force with slightly fewer officers than when Emanuel took office, according to city statistics.

Using police officers for non-police work, such as data entry, graphic design or grant writing, is expensive because they typically make more than civilians in the same jobs. It also diverts them from deployments in city neighborhoods, where officials say they’re needed and where residents want them.

A 2013 report by the office of city Inspector General Joe Ferguson concluded that the Chicago Police Department could save between $6.4 million and $16.6 million a year if civilians replaced officers in “non-operational” positions in its many administrative and support units.

In those units, 370 police officers were working desk jobs in 2013. By this year, that number had grown to 798. If officers were moved out of such jobs, they would be free for “high priority missions” involving more direct police work, according to the inspector general’s report.

At the time, the mayor called the report “useful and instructive.” He promised to move more officers to the street.

The mayor’s office didn’t respond to requests for comment from ProPublica Illinois.

Anthony Guglielmi, a spokesman for the police department, said it continues to work on “civilianizing” positions and putting more police on the street. But he acknowledged that sworn officers have been moved into some administrative units, including the department’s human resources office.

Those assignments were made on a “short-term basis,” Guglielmi said, to help with the department’s two-year hiring plan and “reform efforts.”

“The process of replacing sworn members with civilians can be a lengthy process as it’s vital to ensure that the appropriate candidates have the necessary skills, knowledge and abilities to advance the department's efforts,” Guglielmi wrote in an email.

The department wouldn’t explain why the number of police in some units had ballooned.

For example, in its Alternate Response Section — which handles phone calls related to non-emergency incidents such as burglaries and property damage — the number of positions held by officers grew from 36 in 2013 to 149 this year, the records show.

Though the inspector general recommended that all the jobs in the unit be filled by civilians, only police officers can fill the positions under an agreement with the union that represents those workers, Public Safety Employees Union, Unit II. Officers who can’t go on the street for medical reasons, or because they’re facing disciplinary action, may also be sent to the Alternate Response Section, said Guglielmi.

“Those numbers fluctuate depending on assignments,” he said.

Dozens of officers also filled jobs in the department’s Field Services Section, whose duties include identifying fingerprints, processing warrants and updating criminal history records. Four years ago, Ferguson’s office recommended hiring civilians for 31 of the unit’s 37 positions then held by police officers.

Instead, the number of sworn officers in the section has shot up to 132, according to city records.

Derek Webb, a warrant extradition aide, said civilians held most of the jobs in the unit when he started there more than 20 years ago. But “every time somebody retired or died, they brought a police officer in to replace him,” said Webb, president of AFSCME Local 654, whose members include civilian workers in several city departments. “Over the years, even the clerks and lower positions were filled by police officers.”

Occasionally, the police officers are deployed to the street, he said.

“They’ll be out for two or three months, but then they’ll come back and bring more with them,” he added.

Webb said the police officers get most of the unit’s opportunities to work overtime. He has filed grievances over the practice.

Employees of the Field Services Section collected $819,873 in overtime pay between January 2014 and July 2016, according to an October report on police overtime from the Inspector General’s Office. Another $344,777 in overtime went to the Alternate Response Section. The report found that officials didn’t adequately monitor such payments across the police department as its total overtime tab grew to $146 million last year.

Alderman Scott Waguespack of the 32nd Ward said the mayor hasn’t delivered on his promises.

“Either the mayor isn’t paying close attention or his budget people aren’t,” said Waguespack, chair of the City Council’s Progressive Caucus. “The promises ... need to be kept, especially when we’re so in need of officers on the street.”

At the same time, city payroll records show hiring hasn’t kept pace with the mayor’s pledge to add close to 1,000 more officers to the ranks. As of September, the department had 10,708 personnel with the title of police officer — an increase from recent years but 215 fewer than in June 2011, soon after Emanuel took office.

Of those police officers, 1,016 were working as detectives. In 2011, there were 1,008 detectives before the number fell to 847 in 2014.

Alderman Toni Foulkes, whose 16th Ward includes much of the Englewood neighborhood on the city’s South Side, said the area is well staffed with police, which she credits for a drop in crime totals there this year.

“Since I ran for alderman,” she said, “my thing was, ‘Deploy the police where they’re needed.’”