It began when McCoy tweeted he was on vacation in Puerto Rico. A woman identifying herself as "Steph" replied, saying McCoy should be more involved in his child's life. The baby was born in April, Philly.com said Sunday.
The woman suggested McCoy has a sexually transmitted disease and made other disparaging remarks, leading McCoy to urge his fans and followers to harass her.
Tweeted McCoy: "Tell @Angelface0330 to get a job n stop begging for child support money she a BUM needs me to LIVE sad!!!"
He went on to call her a "nobody" and professed to having sex with her before he knew her name.
McCoy's agent didn't respond to requests for comment.
2014: The Year in Music [PHOTOS]