Griffin explained the fracas on The Howard Stern Show on April 8.
"I couldn't sleep so I went on Twitter and said I'm going to tweet things using Siri, but I'm not going to correct any of the spelling," she said. When a fan asked "Who's the douchiest person you've met?" Siri responded "Debbie Lovato is a little douche."
That's when "the death threats started a flowing," she said. After a brief (now deleted) retort from the singer, Lovato, 21, asked her fans to stop the hate.
"I love you guys so much but y'all gotta chill with sending hate towards other people," she said. "Regardless of what they say or do.. The cruel things some of you are saying can really, REALLY hurt people. It's called cyber-bullying and somethings should NEVER be wished upon EVER. No matter WHAT."
Griffin read Stern some of the most intense tweets she received including: "@kathygriffin I will burn your house down c**t," "@kathygriffin I will come to your house and rape you bitch #lovaticswantkathygriffindead," and "@kathygriffin don't you ever talk s**t about Demi again or else us Lovatics will kill you in your self. Get cancer please slit your f**king throat."
The comedian found some of the tweets comical, but said their extreme nature provoked the police to reach out to her.
"They actually contacted me," Griffin said of the authorities. "At that point it goes beyond Twitter hate."
Though she said Lovato isn't off limits in her standup show, Griffin did explain, "The point is I have no problem with Demi Lovato or Debbie."