Michael Slager, a South Carolina police officer charged with the murder of Walter Scott, had an excessive force complaint against him in 2013. Reuters/Randall Hill

A North Charleston, South Carolina, man told the Associated Press on Thursday that he filed an excessive-force complaint in 2013 against the police officer who was charged with the murder of Walter Scott this week, but that authorities never properly investigated the case. Had they done so, it's possible that Slager could have been dismissed by the police department back then, preventing him from killing Scott, 33-year-old Mario Givens said.

In that 2013 incident, Slager and a partner approached Givens’ front door just before dawn and requested that he come outside, but they failed to offer Givens a reason for the request, Givens said. Slager then threatened to use his Taser on Givens if he refused to comply, so Givens raised his hands and Slager then dragged him outside, Tased him multiple times and then arrested him, Givens said.

It later became clear that Slager had mistaken Givens for his brother, who was being sought following a 911 call by his ex-girlfriend, and the charges against Givens were dropped. Givens filed a complaint and multiple witnesses reportedly offered statements corroborating Givens’ complaint, but investigating officers did not accept those statements, an AP investigation found. The police department then "exonerated" Slager.

The woman who called 911, Maleah Kiara Brown, was at the scene during Givens’ arrest. She said she tried to tell the officers they had the wrong suspect, but they still followed through with the arrest. “He looked nothing like the description I gave the officers,” Brown said.

Slager, who maintained that he shot Scott on Saturday during a routine traffic stop because Scott reached for the officer's Taser, was fired by the North Charleston Police Department on Wednesday after video surfaced showing Slager firing multiple times at Scott's back as the 50-year-old ran away from the officer. The video does not show Scott reaching for Slager’s Taser.