Laquan McDonald, a black teenager with a knife, was shot and killed by a Chicago police officer in 2014. This has become a familiar story in Chicago and across the country — there were approximately 1,200 police killings in 2015.

McDonald’s killing was different -— a video of the shooting was released last fall, 13 months after his killing. The video set off a firestorm of protest that continues to reverberate throughout the city.

The graphic video shows McDonald being hit with a fusillade lasting 13 seconds, resulting in his lifeless body falling to the pavement. Protesters called for the resignation of the police superintendent, the Cook County prosecutor and Chicago Mayor Rahm Emmanuel.

The officer involved in the shooting, Jason Van Dyke, was charged with first-degree murder after the video’s release. The police superintendent Garry McCarthy was fired and Prosecutor Anita Alvarez lost her bid for re-election.

The outrage in Chicago after McDonald’s murder was palpable. The anger quickly brought about changes, even beyond the removal of high profile law enforcement officials. The Police Department began requiring that all officers complete detailed reports for every street stop, according to the Chicago Tribune.

The new policy is intended to protect Chicagoans from racial profiling, improve relations between the police and public, and help reduce incidents of excessive force.

Whenever there is a change in policy, there are often unintended consequences. First the policy change has not only kept officers busy with additional paperwork, but it has also increased their anxiety about being subject to intensive scrutiny regarding every stop they make.

Police told The Tribune that the McDonald shooting has made them less aggressive on the streets out of fear that doing even basic police work would get them into trouble.

Sure the police may feel betrayed by a public that they put themselves on the line for every day — but would an entire department, in one of America’s largest cities, passively go about its work to the peril of its citizens.

Since January, officers have recorded 20,908 instances in which they stopped, patted down and questioned people for suspicious behavior, compared with 157,346 in the same period last year, reported the New York Times. Gun seizures are also down — 1,316 guns have been taken off the streets this year compared with 1,413 at this time last year. The result — officers made 6,818 arrests in January, a 32 percent drop from nearly 10,000 arrests a year earlier.

Big deal, the police are being more cautious. It is indeed a big deal and here is why — recent violence in Chicago has reached levels unseen in years, putting the city on course to top 500 homicides for only the second time since 2008.

As of the end of the month, homicides totaled 135, a 71 percent jump over the 79 killings in the same time last year. Those numbers represent the worst first quarter of a year since 1999, according to The Tribune.

Shootings have jumped by comparable numbers as well. At least 727 people had been shot in Chicago so far this year, a 73 percent rise from 422 a year earlier, according to a Tribune analysis of police department data.

Despite the increase, according to New York Magazine, the numbers are far below the figures from the early 1990s when the homicide count hovered around 900.

However, New York, a city with almost three times the population of Chicago, has only 60 homicides so far this year, a 20 percent drop from last year.

Freedom and liberty come at a cost. If Chicago is any indication, greater protections from profiling, aggressive police tactics and excessive force may be paid for in the blood of innocents.

— Matthew T. Mangino is of counsel with Luxenberg, Garbett, Kelly & George P.C. His book, “The Executioner’s Toll, 2010,” was recently released by McFarland Publishing. You can reach him at mattmangino.com and follow him on Twitter at @MatthewTMangino.