Cops: S.C. couple murdered to keep them from testifying CHARLOTTE, N.C. - Six people are charged in connection with the October 2014 deaths of a husband and wife who were shot when they answered a knock on the door of their South Carolina home. Prosecutors said Wednesday they believe the couple was killed to prevent the husband from testifying against gang members who tried to rob their Charlotte, North Carolina mattress store. Four of those charged in the deaths of 63-year-old Doug London and his 61-year-old wife Debbie were already in custody. Police arrested two more suspects Wednesday, when they also unveiled the indictments. Police say the six belong to the United Blood Nation gang. In May 2014, Doug London fired shots at three men who tried to rob his store, hitting one in the stomach. Later that year, the couple was killed in their Lake Wylie, S.C. home. According to CBS affiliate WBTV, the couple's son, Daniel London, found his parents and called 911. Family said that "[Daniel] said he heard gunshots, woke up and he saw them shot." The station reports that Jamell Lamon Cureton, David Lee Fudge, Randall Avery Hankins II, Malcolm Jarrel Hartley, Briana Shakeyah Johnson and Rahkeem Lee McDonald are accused in the killing of the Londons, according to court documents released on Wednesday. Cureton, Fudge and Nana Yaw Adoma previously robbed the couple's mattress store and the gang members were attempting to stop the Londons from testifying, reports the station. On Oct. 1, 2014, Hartley and Johnson conducted surveillance of The Mattress Warehouse of Pineville in an attempt to locate the Londons and kill them, court documents reportedly state. They not only wanted to prevent the Londons from testifying, but documents say they wanted to retaliate against the couple for previous court appearances related to the robbery case. Doug and Debbie London were popular, long-time residents of Lake Wylie. Relatives and friends said there wasn't anything about them that invited the violence that claimed their lives.