The number of recorded sexual offences involving online dating sites and apps has almost doubled in the last four years, police figures suggest.
Offences where a dating site was mentioned in a police report increased from 156 in 2015, to 286 last year, according to figures from 23 of the 43 forces in England and Wales.
The Online Dating Association said apps try to protect users from harm.
But the National Police Chiefs' Council said firms had a duty to do more.
The figures reveal that between 2015 and 2018 there were a total of 2,029 recorded offences - including sexual offences - where an online dating website or app was mentioned in a police report.
In 2015, 329 offences were recorded, compared to 658 recorded offences last year.
'They should double-check'
Victims told BBC's 5 Live Investigates more should be done by the companies operating the apps to prevent predators from using them to seek out victims.
They called on companies to ask for proof of ID documents and to carry out criminal record checks to prevent offenders from using dating apps to target victims.
Katherine Smith, 26, was stabbed to death by Anthony Lowe in September 2017, two months after they met on the website Plenty of Fish.
Ms Smith was stabbed 33 times, receiving wounds to her back, heart and lungs.
Lowe pleaded guilty to murder at Cardiff Crown Court last year and was jailed for a minimum of 18 years.
His trial heard how Lowe faked his identity to meet Ms Smith, saying he was 10 years younger and that his name was Tony Moore. He did not mention his criminal past.
Katherine's mother, Debbie, said: "They should double-check people before they let them on to these sites, it's so easy.
"If Katherine had known he had a criminal record she wouldn't have gone out with him."
Ten million people
The National Police Chiefs' Council said firms have a social responsibility to prevent abuse on their platforms.
"This would assist law enforcement to concentrate resources on offenders who pose the most harm to the most vulnerable in our society."
George Kidd, chief executive of the Online Dating Association which represents some of the online dating and app companies, said they are unable to do criminal record checks on users but do work with police and are committed to doing all they can to help keep people safe.
"A third of relationships start this way and 10 million people use them in the UK. It's part of our social fabric, we want to celebrate it and make sure it's safe," he said.
Match Group, which owns Plenty of Fish, said it uses "industry-leading automated and manual moderation and review tools, systems and processes - and spends millions of dollars annually - to prevent, monitor and remove people who engage in inappropriate behaviour from our apps".
"Match Group takes the safety, security and well-being of our users very seriously - we consider it our top priority," it added.
You can hear more on 5 Live Investigates at 11:00 BST on Sunday 14 April - or catch up later on BBC Sounds.
BDST: 2116 HRS, APRIL 14, 2019