TMZ Sports has obtained police dispatch audio connected to Marshawn Kneeland's death ... which reveals the Dallas Cowboys player told his family goodbye in an apparent mental episode.
The clip is from late Wednesday night -- operators in Texas are heard relaying information from Kneeland's girlfriend, who stated she received a concerning message from the 24-year-old and was trying to contact the defensive end's agent.
The girlfriend said Kneeland was armed and had a history of mental issues .