It is now more than five years since Lorin LaFave lost her teenage son, Breck Bednar. He was just 14 when he fell under the spell of computer engineer Lewis Daynes, an 18-year-old stranger who groomed him through an online gaming forum, before luring him from his Surrey home to a flat in Grays, Essex, where he slit his throat during an attack believed to be sexually motivated.
The brutal murder in February 2014 of the "handsome, polite and clever" teenage boy - "an everyday good kid", says his mother - left his family devastated and shook parents across the UK.
It also brought to the fore the question of just who our children are communicating with when they're online, and how we can keep them safe in the vast, unchartered terrain of what has been termed the "Wild West Web".
This week, British ministers finally unveiled a White Paper spelling out the Government's plans to bring in the toughest internet laws in the world, in the wake of The Telegraph's campaign to subject tech companies to a statutory duty of care to protect children from online harm.
But LaFave, who now devotes herself to educating children and parents about online safety and lent her backing to our campaign, is appealing to ministers to go further - not least in improving the way police and social media firms investigate harmful accounts online.
Her 17-year-old daughter, Chloe, has received a series of disturbing messages over Snapchat purporting to be from her brother's killer, threatening to desecrate Breck's grave and to harm the family. But the messaging app company has refused to identify who was behind them until the request is formally approved under a treaty with the US, which could take a year.
"Snapchat and police said they can't do anything... they pushed it back and forth on to each other," LaFave told the BBC yesterday. "[Ministers] have to be able to get the police and social media platforms to co-operate rather than saying there's nothing we can do," she said. "It should be quick, at the click of button, to find out who is behind the profiles."
LaFave, a mother of four who moved to Britain from her native US 21 years ago, was no fool when it came to her son's screen use.
"I had parental controls put on. I'd taught Breck how to use privacy settings and had restrictions on when the Wi-Fi would go off in the evening," she told me when we met last year.
"But he was extremely tech-savvy and ran circles around me."
She found out later that her son's murderer had sent him three routers to circumnavigate her restrictions. Daynes, who went by the online name EagleOneSix, befriended Breck in 2013 through a gaming website, where he and his friends communicated through a piece of software called TeamSpeak, akin to a telephone conference call.
The first time LaFave heard Daynes's voice, she was suspicious. "He sounded like a man," she recalls. "Conversely, the boys didn't consider him a danger because he was only 18. They considered him a friend."
She soon noticed changes in her son's personality; he started to refuse to do "the normal family things we did", which she blamed on Daynes's negative influence. She even phoned Surrey Police to report her concerns he was being groomed, but they were not investigated.
After Daynes was sentenced to life imprisonment for Breck's murder in February 2015, it was revealed he had previously been arrested on suspicion of raping another teenage boy. In March 2016, the force offered LaFave and her ex-husband an unreserved apology and substantial damages after admitting serious mistakes in its handling of the case.
LaFave suspects her fears might have been taken more seriously had they related to one of her two daughters, but her message is clear: if a boy like Breck can come to such harm online, then so can any child.
"The Government needs to allow funding so police have the access they need to spot predators," she says. "We need more police who are tech savvy and can be on top of it."
The determined 51-year-old has set up the Breck Foundation, a charity that uses her son's story to raise awareness of playing safe online, and visits schools to spread the message.
"Breck and his friends all had internet safety assemblies, but they weren't engaging and they didn't touch them in any way," she says. "They just thought, 'Oh, more rules'.
"But sadly, they will be talking to strangers as they spend more time online. That's why it's important we teach them about healthy relationships, using appropriate words and not being afraid of talking about paedophiles, predators, grooming and even what people might want to do with them."
She suffered post-traumatic stress disorder following Breck's death, which still returns at times.
"I struggled to leave my bedroom, I lost a lot of friendships because I couldn't act normal," she says.
But working with the foundation and participating in the Duty of Care campaign has given her a renewed sense of purpose: "We need parents to be able to feel their children are safe."