Gia Allemand -- Boyfriend Said, 'I Don't Love You Anymore'

"Bachelor" contestant Gia Allemand had a fight with her boyfriend hours before she killed herself, and he told her "I don't love you anymore."

Gia had accused NBA basketball player Ryan Anderson of being unfaithful during lunch the day she died. During the ride back to her house -- where they stopped at a Walgreens to get her NyQuil -- Gia told Ryan she still loved him but then he dropped the bombshell about his feelings.

We broke the story ... Gia hanged herself in her New Orleans home. According to official docs -- obtained by TMZ -- Gia used a vacuum cleaner cord to end her life. It was tied to the center section of her spiral staircase and tied to the handrail on the second floor.

It appears Gia was on the phone with her mom when she hanged herself. Her mom told cops during the call the phone "had gone silent" and the mother tried in vain to communicate with her for 10 minutes.

Ryan went back to the house to check on Gia, and found her sitting on the stairs with the cord "wrapped around her neck many times." She had been without oxygen for 30-40 minutes.

Gia left a suicide note on the dining room table and in it left all of her property to her mother.