POLK COUNTY, Fla. – An argument between a couple escalated into a man killing his girlfriend and shooting their roommate as that woman tried to protect her, according to the Polk County Sheriff’s Office.Deputies said 33-year-old Christopher Pequeen and his girlfriend recently moved into an apartment in Bartow along with another man and a woman who are in a relationship with each other.On Sunday morning, Pequeen and his girlfriend got into an argument and that woman went into the other couple’s room and told them that “she was scared that Pequeen was going to kill her and that he had held his hand over her nose and mouth so that she could not breathe,” a news release said.[TRENDING: Eta drenches Florida | 2 killed in Orange County crash | Bi.