Kevin Matthews was shot to death during a struggle with an officer who had chased him along the Dearborn-Detroit border around 12:30 p.m. Wednesday, Dec. 23, 2015, according to Dearborn police.

DEARBORN, MI -- On a 19-degree Monday night in Dearborn, more than 150 marched along Michigan Avenue protesting the police killing of 35-year-old Kevin Matthews, an unarmed, mentally-ill Detroit man, by police the afternoon of Dec. 23.

"Hey, hey, ho, ho, these racist cops have got to go," chanted the group, the majority of them black, and many members of the Detroit chapter of the National Action Network.

"Kevin did not have to die, fight for him," read a sign hoisted by someone standing behind Matthews' mother, Valerie Johnson, and two of Matthews' sisters.

"Dearborn police murdered Kevin Matthews," read Johnson's sweatshirt.

Dearborn police, the same agency that employs the officer who shot Matthews multiple times following a brief foot chase and alleged struggle for the officer's gun, provided escort. Their flashing lights blocked traffic as the chanting mass walked west toward the Dearborn Police Headquarters.

"We just can't keep shooting down unarmed citizens," said Les Little, a 62-year-old Detroiter with the Your Vote is Your Voice political activist organization. "I know the police have a tough job, but that's what they signed up for ... There's a whole line of law enforcement agents who have tough jobs, but they manage to get the job done without shooting unarmed citizens."

Multiple protesters said they're skeptical of the police justification for Matthews's killing.

"It always seems that's the standard for a police officer," said Eric Porter, 33, of Detroit, a National Action Network member. "He was going for my gun and I had to shoot him.

"We always here these excuses, excuses. Just like in South Carolina, where the police officer also said he was going for his gun, and then they had the video of him shooting the guy as he was running away."

Porter was referencing the April 4 shooting of Walter Scott by North Charleston Police Officer Michael Slager. Slager initially claimed he feared for his life because Porter stole his Taser, but a bystander recorded the incident, which contradicted the claim and showed Slager apparently dropping his Taser near Porter as he lay handcuffed and dying.

Porter doesn't trust the investigation to be fair. He'll only feel justice is served if the Dearborn officer is criminally charged and the evidence presented before a jury.

Following the shooting, Dearborn police said the officer, whom they haven't released the name of, was on patrol when he spotted Matthews walking near Tireman and Greenfield in Dearborn.

They said Matthews "was known to be wanted on a probation violation warrant" and "escaped from officers earlier in the day after" after a theft in Dearborn.

The officer exited his vehicle and chased Matthews through several yards across the Dearborn border into the backyard of a Detroit home where a struggle ensued and Matthews was shot.

Detroit police are investigating the homicide.

Detroit Police Chief James Craig told George Hunter of the Detroit News a woman witnessed the struggle, and that when backup arrived the officer's uniform was dirty, torn and his gun holster loosened.

"Release the cops name" and "They shot him down for nothing," individuals in the crowd shouted before the march began Monday.

"Stop police terror, indict killer cops," read several signs.

"We need a standard of conduct as to when deadly force is employed," said Sam Riddle, the Michigan National Action Network's political director. "Certainly a misdemeanor doesn't warrant killing someone.

"Now the standard cover police use, 'He went for my gun, I feared for my life.' Was the chase ... even necessary?"

Detroit and Dearborn police, although they've released few details, maintain the investigation will be conducted swiftly and transparently.

Both agencies have declined to verify whether audio or video evidence of the pursuit and altercation exist, although Dearborn police said their officers do wear on-body microphones and have patrol vehicles equipped with dashboard cameras.

According to Michigan Department of Corrections records, Matthews had no felony convictions on his record.