The former police officer who fatally shot Michael Brown six years ago in Ferguson, Missouri, will not be criminally charged, the St. Louis County prosecutor said.

St. Louis County prosecutor Wesley Bell said his office was unable to prove beyond a reasonable doubt that Darren Wilson committed murder or manslaughter under Missouri law.

Brown's father is expected to publicly call for reopening the investigation.

Brown was unarmed when he was shot and killed by Darren Wilson, a white police officer, in 2014, sparking national protests over police brutality.

Wesley Bell’s win comes nearly four years after Michael Brown was killed by Ferguson Police Officer Darren Wilson.

In 2014, the now 15-year-old Devonte Hart was seen hugging a police officer at the time of protests over the shooting death of Michael Brown in Ferguson, Missouri.

Michael Brown, a black 18-year-old, was fatally shot by a white cop in 2014.

Authorities previously argued that Brown had robbed the store.

A new surveillance video has been released of Mike Brown hours before shooting.

Gunfire erupted as protesters gathered outside the Ferguson Market on Sunday.