After the dismissal of 16 New Haven Police Department officers last week, 17 cops responded with a “sickout” amid the growing tension against City Hall budget cuts and layoffs.

The officers, representing 40 percent of the evening patrol, called in sick for the overnight shift last Thursday — the night after the layoffs — City Hall spokesman Adam Joseph said in a press release Friday. The allegation has prompted an internal investigation into whether the officers had legitimate reasons to shirk their duties, Joseph added. Meanwhile, some city officials are blaming union leadership for its response to the layoffs, the Hartford Courant ran an editorial condemning the police union for overreacting and the New Haven Register reported that officers could face criminal charges for the march and the disruptions and street closures it caused.

Although pressure is mounting from the police union, Mayor John DeStefano Jr. is holding his ground. At a press conference after the protest and in public statements since then, he has refused to grant the union any more time for negotiations before the layoffs.

“I expect the men and women of the New Haven Police Department to do their jobs like everyone else. End of story,” DeStefano said in the same press release.

NHPD Chief Frank Limon has begun an investigation of the “sickout,” Joseph said. The investigation could result in penalties for any officer who Limon proves did not have a legitimate reason to be sick, he added.

Although City Hall alleged that the 17 officers called in sick as a form of protest, the union leadership has publicly bemoaned the understaffed police force in the week leading up to the layoffs and in their immediate aftermath.

Union President Sgt. Lou Cavaliere said after the 16 laid-off officers handed in their badges that he is worried about the department having a dangerously low number of patrol officers. In addition to the layoffs, he said he anticipates as many as 50 retirements in the next year owing in part to low morale.

This threat of punishment follows a police protest on Thursday that brought nearly 250 officers to the streets of New Haven, starting first at the NHPD headquarters on Union Ave. and eventually stopping outside of City Hall. Instead of turning in their badges Thursday morning as they were instructed, the 16 laid-off officers led a precession of their colleagues to the mayor.

“When we were at the police department and didn’t get the answers from [New Haven Chief Administrative Officer Robert Smuts ’01], we decided to come here,” police union treasurer Sgt. Anthony Zona said at the protest. “We came here to get some answers from the mayor.”

As union leadership sought answers inside of City Hall, the protest lasted several hours outside on the steps and the sidewalk. At one point, police closed off Church St. to all traffic to accommodate their own protest. The New Haven Independent reported on Sunday that the state’s attorney’s office will investigate the police conduct during these events.

During the protest, most officers wore their uniforms and several arrived in police cruisers. Still, Zona claimed that every officer present was off-duty.

After the layoffs, the NHPD officially has 434 sworn officers on its payroll. The department may also consider moving some of these officers out of the office and on to the streets to address residents’ safety concerns, Limon told the News Thursday afternoon.

New Haven saw 24 murders in 2010, an 85 percent increase from 2009.