CHICAGO (CBS) — Attorneys for an 84-year-old woman killed in a crash involving a Chicago police van have released surveillance video showing the van hitting an unmarked SUV, and then slamming into the woman’s car at a West Side intersection last month.

Verona Gunn was killed on Memorial Day weekend, when a CPD transport van blew a red light at Laramie and Division, hitting an unmarked police SUV that was crossing in front of it.

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The two police vehicles then crashed into the blue car in which Gunn was sitting. The beloved mother and grandmother died soon after the crash. Ten officers and at least one other civilian also were injured in the crash.

Gunn family attorney Andrew Stroth has claimed the police vehicles were violating department rules requiring them to slow down as they approach an intersection, to make sure it’s safe to proceed.

Mayor Lori Lightfoot has said the officers were responding to a nearby call for a man with a gun at the time of the crash, but Stroth has said that call is not unusual for Chicago, and didn’t require officers to drive the way they did.

Stroth and Gunn’s family met with Police Supt. Eddie Johnson days after the crash to review security footage of the crash. Stroth released that footage Monday night.

“What we saw in the video was an officer in his vehicle driving recklessly, blowing a red light, causing a horrific crash, resulting in the death of Miss Verona Gunn,” Stroth said after the May 28 meeting with Johnson.

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A radio call asked for backup, but soon after officers were told to back off. Moments later, that CPD transport van came barreling through the intersection of Laramie and Division.

“That officer should have yielded and Verona Gunn should be alive today,” Stroth said.

The family car, a Toyota sedan, had stopped as around 10 police vehicles passed through the same intersection before the crash, Stroth said. The car was still idling when the collision occurred.

Stroth has filed a wrongful death lawsuit against the city on behalf of Gunn’s family.

Gunn’s children wept as attorneys played the video of the crash at a Tuesday press conference to announce the lawsuit.

They said the officers never should have been driving as fast as they were that night.

The family is demanding an independent investigation of the crash.

“Our mom’s dead today because of poor policies within the Chicago Police Department. There is a lack of proper training when it comes to police and how they are recklessly driving through our communities. We are not anti-police. We are pro-reform,” said her son, pastor Dwight Gunn.

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In addition to the lawsuit, Gunn’s family said they want to work with Mayor Lori Lightfoot to make sure officers get better training for pursuit situations.