Cerys Yemm killing: Sex offenders housed at Argoed B&B
Previous guests at a B&B where 22-year-old Cerys Yemm was killed by a homeless prison leaver include 10 sexual and violent offenders, the BBC has learned.
The landlady of the B&B in Argoed told Week In Week Out she believes the council has put her and the community at risk by housing them there.
Caerphilly council said it considers risk assessments before sending ex-offenders to temporary accommodation.
Miss Yemm's killer, Matthew Williams, 34, died after being Tasered by police.
The programme has also discovered that when councils in Wales and the rest of the UK have nowhere else to send the homeless in emergencies, some are referring them to hotels like Premier Inns and Travelodges.
These issues have prompted calls by campaign group Voices From Care for an urgent review of the council's handling of the case and a wider investigation by the Welsh government into the reason so many young people, including many care leavers, are sent to B&Bs.
Miss Yemm's mother, Paula Yemm, whom she lived with in Oakdale, has also spoken for the first time.
She said: "There are things I need to know; who made decisions to place him [Williams] there and what, if any, risk assessments were completed and what went wrong?"
Mandy Miles, owner of the Sirhowy Arms, said that, according to her records, the council sent a number of serious ex-offenders to her without warning her or the wider community of the potential risks.
Her B&B was used by the council to temporarily house homeless adults and a number of vulnerable teenagers for six years and she said she was happy to accept them.
Many of the adults had been to prison - others included people with mental health, drug and alcohol issues.
After the deaths of Miss Yemm and Williams last November, local residents used the Freedom of Information Act to ask the council about the type of ex-offenders placed there.
The council said it had referred 10 sexual and violent offenders who were homeless.
Ms Miles insisted she did not know this beforehand.
She said she had since cross-matched her records with news reports on a number of offenders and discovered they included a rapist, a voyeur and several paedophiles.
"I had to Google to find out what they'd done. That annoyed me," she said.
Ms Miles added, according to her records, the council also placed a vulnerable 17-year-old care leaver at her hotel at the same time as a convicted paedophile.
The programme found, in the past five years, Welsh councils sent 755 homeless people to stay in B&Bs because there was nowhere else for them to go.
In England, councils have been told to stop sending 16 and 17 year olds to B&Bs as they are deemed inappropriate.
In Wales, councils can leave them there for up to six weeks at a time while alternatives are sought.
The council refused to say what detail it would provide to Premier Inn and Travelodge if sending homeless people to their hotels as a temporary measure.
Premier Inn said it expected local authorities to assess anyone before sending them and Travelodge said customers had to abide by hotel rules.
Debbie Jones, from Voices from Care, said: "As a corporate parent you have a responsibility as a parent to a child that is in your care.
"They need to be immediately and urgently reviewed in terms of their practices, so again we need to call for a national review to look into, in particular, Caerphilly - but I suspect this is a wider problem than just one local authority."
The council said it considers risk assessments from police and the probation service before sending ex-offenders to temporary accommodation.
It said that while it told Ms Miles if clients were ex-offenders, it did not give her details about the reason they had been to jail.
Conservative AM for south east Wales William Graham believes the council should have shared more information with Ms Miles and is backing calls for an investigation into its handling of the case.
"This case highlights failures and, in that case, perhaps a serious case review is what is needed to identify what the failures are and look at the individuals involved - did they pursue their duty according to their specification and if they haven't done so then disciplinary action clearly must follow," he said.
Inquests are due to be held in the autumn into Williams's and Miss Yemm's deaths.
Her mother hopes it will bring the answers she is looking for about how and why she died at the B&B.
Ms Yemm is also calling for the Sirhowy Arms to be demolished.
She said: "So long as it's there, it's a reminder of what was taken away and if I have to fight to my dying day, I will fight for that to be knocked down - that can't be there."
Week in Week Out, Tuesday 22:35 BST, BBC1 Wales.