CHICAGO (CBS) — Night-time demonstrations in Ferguson, Missouri, seem to be tapering off and police and the National Guard are scaling back, but the parents of slain teenager Michael Brown continue to wrestle with what comes next.

Some people are urging them to seek justice with a civil lawsuit, among them a south suburban man who says he knows their pain, reports CBS 2’s Mike Parker.

In June 2011 in the Englewood neighborhood, a Chicago Police camera-equipped squad car rolled up as another officer walked toward a wounded suspect. The domestic violence suspect lay on the ground, and an officer shot the man three more times.

29-year-old Flint Farmer died, armed only with a cell phone. After two years, no charges are filed against officer Gildardo Sierra.

“The police, certainly with my case were caught dead on camera killing my son and not even being indicted,” said Emmett Farmer, Flint’s father.

State’s Attorney Anita Alvarez says an exhaustive investigation concluded Sierra reasonably mistook the cell phone for a gun.

“Not every mistake demands the action of the criminal justice system,” she said.

The Farmer family filed a civil suit and the city settled out of court for $4.1 million. Emmett Farmer urges the family of Michael Brown to do the same and sue, charging wrongful death.

“Just fight it through the justice system,” Emmett Farmer said. “I’m a man of God. I believe the lord will prevail.”

CBS 2 Legal Analyst Irv Miller said he is reminded of the O.J. Simpson case.

“O.J. Simpson was found not guilty in criminal court, but he was found liable by a civil jury and ordered to pay big, big bucks,” Miller said. “You could end with the same result in Ferguson.”

Emmett Farmer says, “I just pray they get the justice that they need and that they’re seeking.”

The CBS 2 investigators reported two years ago that officer Gildardo Sierra had been stripped of his police powers and was doing desk duty since the shooting of Flint Farmer. A police spokesman tells Parker that is still the case.