No one knows exactly what Grace Millane's family is going through, but Mark Longley probably has a better idea than most.
In 2011, his 17-year-old daughter Emily was strangled to death by her boyfriend Elliot Turner. She was living in the UK at the time of her death, on the other side of the world from her parents and sister in New Zealand.
The tragedy is eerily similar to the death of British backpacker Ms Millane, who'd only been in New Zealand a few weeks.
Mr Longley told Three's The Project (which dedicated its entire first break to honouring the 22-year-old's memory) that he feels for her father David Millane, who arrived in the country last week.
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"We heard he was getting on the plane coming over here, and we were just praying he'd get off the plane and there'd be a text message from Grace saying she'd been in the bush or something," says Mr Longley.
"I think for a father... you want to protect your daughter. You raise them with a lot of love and you want to keep them safe.
"They say they're going off travelling and you give them your blessing - but at the same time, you're worried about it, and you just hope they're going to come back fine."
The journalist spoke about some of the most painful moments following his daughter's death, experiences no parent should have to go through.
"For a father to look at your deceased daughter - I think that's really hard," Mr Longley explained.
"I don't want to detract from how the other members of the family are doing, but to know that somebody's done something to her, put a hand on her with violence and killed her, I think that's hard for a father to take.
"I really feel for him. He's over here on his own, he's a long way from home."
The loss of Emily was earth-shattering, but Mr Longley says a strong support network helped him get through the worst of his grief.
"It was pretty hard to start with, but the rest of my family certainly [helped], my other children and my wife."
His advice to the Millane family is to remember their daughter and sister the way she was, not what happened to her.
"They're are going to go through a tough time, there's going to be a court case, but just really focus on the great things that Grace was and celebrate her life, and don't get caught up in what happened."
After Emily died, Mr Longley got involved with White Ribbon, which campaigns to end violence against women. He says something needs to change about men's behaviour to reduce our high rates of partner assault and murder.
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"I was really appalled at how some of the men outside of the guy who murdered Emily acted. Elliot Turner practised murdering Emily, he talked about how he was going to set fire to her, strangle her. If you're talking about strangling your girlfriend, that girl's life is in danger.
"I was appalled that other people didn't rein him in, so I wanted to find some way to talk to men and say 'If your mate's behaving like this, you've got to do something about it'.
"There's been a lot of anger towards men at the moment, and men are hitting back saying 'I'm not the problem'. You might not be the problem, but you should be part of the solution.
"It's all men, you can't just sit there and say 'It's not me, I'm not doing this'. We need to step up and be part of the solution."
Gil Elliott, whose daughter Sophie was murdered by her ex-boyfriend when she was 22, has also spoken about his empathy for Ms Millane's family.