The mother of an Algiers woman killed during a viral video of a fight said her daughter knew the woman police said pulled the trigger.Monday, Brittany Ussin, 25, was seen in a viral video as two women were fighting near McDonogh Park in Algiers. According to her mother Montrice Ussin, the 25-year-old was not involved in the fight but died after being shot.Ussin’s family told WDSU the two women knew each other with some saying their families have been close over the years.During Thursday’s vigil, the Ussin’s aunt Cotrena McIntyre said she was relieved after the person police say killed her niece was arrested less than 24 hours after the shooting.“I fell to the ground. I could not believe that this happened. You know that they were able to apprehend the shooter so quick,” McIntyre said.Video posted to social media shows women fighting before a gunshot is heard. The family …