They are supposed to be the people you can trust with your life.
But new true crime TV show Murder at My Door sees former Coronation Street star Kym Marsh tell the stories of victims who were killed by those closest to them.
And Kym admits the chilling tales of innocent people targeted by twisted friends, partners and co-workers left her questioning who you can really trust.
She says: “The shocking thing for me was how many people are killed by someone they actually know and love and we don’t think about that.
“Let’s face it, all these victims would never have thought ‘One day you’re going to murder me,’ to the person they’re sat down with having a cup of tea and been friends with for years.
“That’s the scary part of it, who do you trust? It’s the ultimate betrayal.”
Kym, who played Michelle Connor in Corrie from 2006 until she left the show last December, reckons her experience of soap acting has helped her tell the stories of the murder victims in the right way.
“Soap is something that’s very not real,” says Kym. “But being able to tell the stories in the right way, perhaps the skills from my day job have helped.
“I’ve always said television is really important when it comes to getting key messages out to the general public.
“They give people education and insight into issues, whether it’s male suicide, domestic abuse or baby loss.”
And Kym believes one things soaps do “brilliantly” is their research into difficult or taboo subjects.
She says: “Soaps work closely with charities and use case studies. They get everything right and show people what can happen in real life. I think they’re very important and they do help to make a difference.”
Kym has also just been announced as the face of a new domestic violence campaign with Refuge.
The #HereForHer initiative is run by the domestic abuse charity and TV channel Crime + Investigation, which is broadcasting Murder at My Door.
It aims to highlight the huge scale of the domestic violence issue, the types of abuse women experience and what support is available.
During lockdown, Refuge saw an increase in calls to its National Domestic Abuse Helpline and a greater demand for emergency accommodation.
“Many people still believe domestic abuse is a private matter,” says Kym. “Many victims of domestic abuse feel isolated from friends or family due to their abusive partners, and feel like they have no one to talk to.
“That is why I’m championing the initiative to let those victims know there is a community of support available to them, even if they feel like they have nowhere to turn.
“Abuse during the pandemic is something that’s really hit home. There has been a rise in calls to Refuge’s helpline because people have been left isolated at home with their abusers.
“The other thing that concerns me is that because of the pandemic fundraising has been limited. People have been unable to do what they usually do in terms of raising money.
“So, this is why now it’s more important than ever that we do our bit and try to fundraise for our charities.”
One case featured in Murder at My Door is that of Ellie Gould. Ellie was just 17 when she was killed in May last year by her ex-boyfriend Thomas Griffiths, 18, after she ended their relationship.
Griffiths went to Ellie’s home in Calne, Wilts, stabbing her 13 times in the neck with a kitchen knife. And this was the story which affected Kym the most from the series.
“It’s the one I thought about the most afterwards not least because it’s so recent, but because she was so young,” says Kym.
“Being a mum myself it struck a chord with me to think she was murdered by her ex-boyfriend. These were just kids.
“To watch her mum and how brave she was in telling the story, that really stayed with me.”
Other cases featured include 21-year-old Gagandip Singh, whose body was found in a burning car in Blackheath, south-east London, in February 2010. He had been lured to his death by former friend Mundill Mahil after their relationship broke down.
Jenny Methven was killed in February 2012 by her son David’s long-term friend William Kean, who hit the pensioner at least 11 times in the head and left her dead and covered in blood in her Perthshire home.
While Susan Annis, 31, was murdered by her nursing colleague Kevin Cobb in 1996 as they were in the final week of a course at London’s Royal Brompton Hospital.
Sexual killer Cobb had laced Susan’s drink with a rape drug, but his plan to assault her went wrong when Susan fell into a coma due to the drug affecting her underlying heart condition.
Kym narrates Murder at My Door, while detectives, journalists and experts also discuss the investigations and motives for the murders.
And while Kym didn’t interview the victims’ families, saying her job was to “fill in the gaps and tell the stories”, she prepared for presenting the show by watching “a lot of footage”.
“I did witness a lot of the families’ anguish during their interviews,” she says. “It’s just unreal to see how brave they are in discussing something which is so raw for them and it always will be.
“It doesn’t matter how much time has passed, it is something that will stay with them forever. It’s life-changing.
“So many people are killed by someone they know, and that concept is something that I found very interesting,” Kym adds. “There’s an important story to tell and get out there.”
Murder at My Door starts on November 2 at 9pm on Crime + Investigation