CHICAGO (CBS) — Chicago Police believe cellphone video of a merciless shooting that left a man dead and a woman critically wounded in Humboldt Park over the weekend will help them catch the suspects.

But on Monday, CBS 2 Political Investigator Dana Kozlov learned one video of those crimes that was posted on social media came straight from a city camera – and should never have been made public.

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Outrage has erupted over the cold-blooded murder of Gyovanny Arzuaga, 24, and the shooting of his girlfriend, Yasmin Perez, 25. Both were gunned down around 9 p.m. Saturday on Division Street near Spaulding Avenue during a post-Puerto Rican People’s Parade celebration – after what police said was a minor traffic accident.

More than one video of the shooting has been posted to social media. Sources told the CBS 2 Investigators that one such video – still on Twitter at our last check – is from a city pod camera located on the same pole as a shot spotter sensor.

In that tweet, police radios or similar transmissions are clearly heard in the background as at least two men discuss what they are seeing.

It is footage that could help detectives track down Arzuaga’s killer. He was shot by a man wearing a sleeveless white shirt after the young father tried to shield Perez, who had already been beaten and shot.

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“You see that second suspect clearly just holding a gun, shooting him in the head almost execution-style,” said Chicago Police Chief of Detectives Brendan Deenihan.

But the pod cam footage was released without the permission of the city or the Chicago Police Department – raising questions about who accessed it and then recorded it on a cellphone before posting it to the web.

A Police Department spokesperson said detectives at Area Five are handling the investigation. But when Kozlov asked about the video that sources came from that city pod cam, the spokesperson would only say the city did not release the video – so they cannot confirm anything or say if it is being investigated.

However, a spokesperson for the city’s Office of Emergency Management and Communications confirmed the video is the subject of an investigation, but did not provide anymore details. In the meantime, Mayor Lori Lightfoot said the hunt for the suspects is a top priority.

“The fact that that happened in our city, and so many individuals stood around and seemingly were trying to take advantage of this moment is a horrific statement,” Mayor Lightfoot said.

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We chose to blur the name of the person who tweeted the video that is the subject of this story, out of respect for the victims’ families.