Schoolgirl Molly Russell used an anonymous Twitter account to reach out to celebrities and influencers for help, an inquest has heard.
The 14-year-old sent tweets to American actress Lili Reinhart and YouTube star Salice Rose, with one saying: “I can’t do it any more.”
Molly’s father, Ian Russell, was taken through the posts from the witness box on Thursday, where he said: “I believe social media helped kill my daughter.”
He said the messages sent to high profile figures were “particularly prevalent on Twitter”.
Mr Russell told North London Coroner’s Court that harmful and “normal” online content would have been “conflated” in a 14-year-old’s mind.
He was asked about his thoughts on the effect of Molly accessing “harmless” content on social media platforms, such as posts about fashion and pop music, by the family’s lawyer Oliver Sanders KC.
Giving evidence in the witness box on Thursday, Mr Russell said: “I believe social media helped kill my daughter.
“I believe that too much of that content is still there and I believe there is a lack of transparency.
“Children shouldn’t be on a platform that presents a risk to their lives.”
Mr Russell was taken through tweets to celebrities where his daughter said she “just can’t take it”.
One tweet, sent to Ms Reinhart by Molly, which was read to the court on Thursday, said: “I can’t take it any more.
“I need to reach out to someone, I just can’t take it.”
Mr Russell said: “It’s exactly that type of message … that was particularly prevalent on Twitter.
“On the Twitter platform… she reached out to celebrities with thousands or millions of followers who wouldn’t even notice one small tweet from someone like Molly.
“She was never really going to get a response.”
Other tweets, directed at YouTuber Ms Rose, said: “I can’t do it any more. I give up.”
Another said: “I don’t fit in this world. Everyone is better off without me.”
The court was told these tweets were sent a few months before the teenager died.
Mr Russell said the schoolgirl seemed to be “back to her normal self” shortly before she died.
The 59-year-old said his daughter seemed “excited” about things in the future and that in the two months before her death he thought the “passing phase she was going through had passed”.
The inquest, which is expected to last up to two weeks, continues.