Attorneys for the family of Michael Brown announced Thursday they are filing a wrongful death lawsuit against Ferguson, Missouri and Darren Wilson, the officer who shot and killed the unarmed black 18-year-old last August.

Brown's death on August 9, 2014 sparked civil rights protests around the country, which continued to grow after a series of high-profile police killings of unarmed black men and women.

"We are officially in the process of formulating a civil case that we anticipate will be filed shortly on behalf of the family," said Anthony Gray, one of the family's attorneys, during a press conference Thursday.

The announcement comes a day after the U.S. Department of Justice said it would not bring federal civil rights charges against Wilson for killing Brown.

Referring to that decision and the grand jury hearings which previously cleared Wilson of wrongdoing in November, Gray said, "In our case, we plan to show and outline pretty much the same evidence; however, you will get a more... accurate [view] of what took place that day."

Another attorney for the Brown family, Daryl Parks, said during the press conference that the Justice Department has "accepted [Wilson's] self-defense. We do not accept his self-defense."

On Wednesday, the Justice Department also released a report on the Ferguson Police Department revealing systematic and often brutal racial prejudice among law enforcement in the city.