(CNN) A Chicago police officer says he shot and killed a black man this week after the man twice pointed a weapon at him, but so far investigators have not found the weapon, authorities say.

Police are investigating the death of the man -- identified by his family as Kajuan Raye, 19 -- which comes after months of heavy scrutiny of the department over cases of alleged overreach in officer-involved shootings.

"We were not able to locate a weapon (of Raye's) as of yet," police Superintendent Eddie Johnson told reporters Thursday. "There's still many unanswered questions and we are working diligently to find those answers."

The shooting

Police say a sergeant was called to an intersection near Ogden Park on the city's south side late Wednesday about a report of a "battery in progress."

Kajuan Raye was a "fun-loving and happy kid who had a bright future," his family said.

When the sergeant approached a man who he says matched the description of a suspect, the man -- who turned out to be Raye -- ran, and the sergeant chased him, police say.

"The sergeant then told investigators that the offender turned and pointed a weapon in the direction of the sergeant on two separate occasions during the pursuit," Johnson said.

The sergeant shot the man, killing him, Johnson said.

Investigators searched the area overnight, but they have not found the weapon that the man is alleged to have had, the superintendent said.

Police have not released the sergeant's name. He will be taken off patrol and placed on administrative duties for at least 30 days, as is routine for officers involved in a shooting while it is reviewed.

Video taken by two surveillance cameras outside a church shows Raye running and the officer chasing him out of the cameras' view, CNN affiliate WLS reported. The footage does not show the shooting.

Family's lawyers call for prosecution

Raye's relatives said he did not own a gun, WLS reported.

Raye, of Dolton, just south of Chicago, was a "fun-loving and happy kid who had a bright future," his relatives said in a statement released by the Montgomery Law Firm, which says it is representing the family in the case.

Raye's family is "heartbroken that their son is dead at the hands of a police officer who does not value the sanctity of life of black males," the statement reads. "As a city we continue to struggle with police who are afraid of and have deep seeded prejudices against black youth.

The family has asked its lawyers to "investigate, get answers and hold accountable this officer and Chicago Police Department," the statement reads.

A lawyer with the firm, Jay Payne, told CNN the claim that Raye pointed a weapon is absurd, given that police haven't found one after what Johnson said was a grid search of the area.

Payne said Raye was waiting with a cousin for a bus when the officer approached him.

"We will be asking the Cook County state's attorney to prosecute this officer," Payne said.

Chicago police under fire over shootings

Raye's death comes more than two years after the shooting by Chicago police of 17-year-old Laquan McDonald , a case that spurred reforms and protests and helped fuel a national conversation about police officers' use of deadly force.

McDonald's death in October 2014 went largely unacknowledged until a judge ordered the department to release dashboard-camera footage that contradicted officers' accounts of the shooting.

Just before the video was released in November 2015, Chicago police Officer Jason Van Dyke was charged with first-degree murder in the McDonald case; he pleaded not guilty and is awaiting trial. He was the first Chicago officer charged with first-degree murder since 1980.

The superintendent of police at the time of the McDonald shooting, Garry McCarthy, was fired by Chicago Mayor Rahm Emanuel this year , and the Independent Police Review Authority, the agency charged with investigating police-involved shootings, is being overhauled.

Years of mistrust

Emanuel created a Police Accountability Task Force in response to public outcry for accountability and transparency after the release of the McDonald shooting video.

In April, a report from the task force said police "have no regard for the sanctity of life when it comes to people of color" and have alienated blacks and Hispanics with the use of force and a longstanding code of silence.

During the past eight years, 74% of people killed or injured by Chicago police officers were African-American, the report said.

The task force, which included five Chicagoans who have been leaders in the justice system, found that 72% of people stopped by Chicago police in 2014 were African-American, and 17% were Hispanic.

To address the slew of systemic issues within the police department, the task force recommended nearly 100 changes. Emanuel has announced the implementation of nearly one-third of those recommendations, including replacing the Independent Police Review Authority with an agency that has "more independence."