The mother of murdered teenager Brianna Ghey has called for smartphones to be made available for under-16s without social media apps.
She is also campaigning for searches for inappropriate material to be flagged to parents.
Scarlett Jenkinson and Eddie Ratcliffe were both 15 when they killed Brianna, 16, with a hunting knife after luring her to Linear Park, Culcheth, a village near Warrington, Cheshire, on February 11 last year.
Jenkinson had watched videos of torture and murder online.
Speaking on the BBC’s Sunday With Laura Kuenssberg, Esther Ghey said: “We’d like a law introduced so that there are mobile phones that are only suitable for under-16s.
“So if you’re over 16, you can have an adult phone, but then under the age of 16, you can have a children’s phone, which will not have all of the social media apps that are out there now.
“Also to have software that is automatically downloaded on the parents’ phone which links to the children’s phone, that can highlight key words.
“So if a child is searching the kind of words that Scarlett and Eddie were searching, it will then flag up on the parent’s phone.”
She said if the searches her daughter’s killers had made had been flagged, their parents would have been “able to get some kind of help”.
Ms Ghey said her transgender daughter had accessed pro-anorexia and self-harm material online and been “very protective” over her phone, which had caused arguments.
“If she couldn’t have accessed the sites, she wouldn’t have suffered as much,” she said.
Describing the internet as the “Wild West”, she said the focus of technology had been on making money rather than “how we protect people or how we can necessarily benefit society”.