The family of Michael Brown, the unarmed black teen shot to death by a police officer in Ferguson, Missouri last August, is following through on its promise to file a civil suit against the city for wrongful death, according to a statement Wednesday evening by the family's lawyers, Benjamin Crump and Daryl Parks.

A formal announcement is expected Thursday morning.

The lawsuit has been expected since early March, when the family first stated their intention to file charges against Ferguson and Officer Darren Wilson, who killed Brown. It comes in response to the Justice Department's decision not to bring federal civil rights charges against Wilson, which came shortly after he was cleared of wrongdoing by a grand jury.

"They have accepted [Wilson's] self-defense," Parks said at the time. "We do not accept his self-defense."

As the Guardian notes, the action is "likely to be the Brown family’s final opportunity to hold authorities responsible for the death of their son."

Brown's death sparked a wave of protests against racial profiling and police brutality that spread across the globe. The movement was fueled by continued incidents of black men, women, and children being killed by police, many of which were caught on video.

Also in March, the Justice Department released a report on the Ferguson Police Department revealing systematic and often brutal racial prejudice among law enforcement in the city. That report led to a wave of resignations from city officials, including the police chief, city manager, and a judge who acted as a chief engineer in creating Ferguson's "debtor's prison" justice system.