(CBS) — The city plans to release what’s being called a shocking police dash-cam video of a vandalism suspect being shot to death by a Chicago police officer, but no timetable has been set.

CBS 2 Chief Correspondent Jay Levine spoke with two men who have seen the video. They have mixed emotions about its release.

They’re concerned, in part, about the reaction the video could generate.

Jeff Neslund and Mike Robbins subpoenaed the police dash cam video, which captured the shooting of 17-year-old Laquan McDonald, an African American. Last year, he was allegedly under the influence of drugs and slashing tires of parked cars with a knife. The video shows McDonald being shot 16 times by a single officer.

Robbins describes the shooting as being “like an execution.”

“The first shot or two seem to spin him on the ground. He falls down. He’s down on the ground, and for the next 30 seconds or so, in this video, the officer just continues to shoot,” Neslund says.

He adds: “What you see are graphic puffs of smoke rising from Laquan and intermittently his body twitching, in reaction to the shots.”

Mayor Emanuel on Friday said the highly sensitive should eventually be released publicly.

“There’s an appropriate way to handle when videos become public and that procedure will be followed,” he said.

A spokesman for the mayor said the city will release the video “as soon as its release does not impede the investigation(s).”

The officer who did the shooting has been stripped of his police powers pending the outcome of a federal investigation. He’s a 14-year veteran, the subject of 18 complaints or allegations, none of them sustained by police investigators – and also two federal lawsuits, one of which cost the city more than $500,000.

Following the death of McDonald, the city paid his survivors $5 million.

The officer under investigation says the suspect lunged at him with the knife. The videotape apparently tells a different story: of a white cop and black suspect that some say might be inflammatory.

City Hall and police headquarters are just starting to talk about how to release the tape if ordered by a judge following a hearing next Thursday. But Friday, the American Civil Liberties Union said the city shouldn’t wait to be ordered to release the tape and should release it now.