Sonya Massey's father is sharing his heartbreak after his daughter was shot and killed in her home by a white police officer ... slamming the deputy as a devilish figure.

James Wilburn spoke with Gayle King on "CBS Mornings" after body cam footage of the shooting showed Sangamon County Sheriff's Deputy Sean Grayson shooting Massey earlier this month ... this after she'd actually called 911 for help.

According to her dad, he claims he was never told a deputy was involved with the untimely passing of his daughter, and says he was led to believe an intruder shot and killed his daughter. JW said he learned about the facts of the case from his brother ... and felt they had been misled as part of what he characterized as an alleged "cover-up."

He says he's thankful the body cam footage came out -- otherwise, he may have never truly known what happened to Sonya.

As for her final words -- "I rebuke you in the name of Jesus" -- Wilburn says he felt his daughter knew her life was in danger. He even labeled Grayson as an "emissary of Satan."

As we reported ... body cam footage of the shooting sparked widespread outcry, as it showed Grayson opening fire on Massey over a boiling pot of water she was clutching. Grayson defended his decision to shoot in the video -- citing the water as a possible threat.

Grayson has since been fired and is now facing charges of first-degree murder, aggravated battery with a firearm and official misconduct. He has pled not guilty.