Cerys Marie Yemm, 22, died after being attacked by Matthew Williams at a hostel in Argoed, Caerphilly county.
Police used a Taser stun gun on the 34-year-old and he later died.
Reverend Charlotte Moss, of Argoed Baptist Chapel, said: "The tragedy is that Cerys suffered as a consequence of someone else's internal battles."
She said: "A young light was taken and it has caused shock here in this quiet community," she told a congregation of 60 people.
"Our heartfelt feelings of sympathy go to both Cerys's family and the family of the man responsible," she added.
Prayers were said for Ms Yemm as the chapel held its annual service of remembrance on Sunday.
Reverend Moss said: "This week there has a been a violent death of a young woman in our village.
"This has caused sorrow and pain for her family, her friends and her neighbourhood.
"There was also sorrow and pain of the person who caused this act of violence and the family and community where he came from."
A serious further offence review will take place into the case, which happened shortly after Williams was released from prison, the Ministry of Justice confirmed on Saturday.
Details of Williams's previous offences and the length of sentence he received have not been confirmed.
Serious further offence reviews are held if crimes are alleged to have happened within 30 days of a sentence ending.
The Independent Police Complaints Commission (IPCC), which is investigating the circumstances surrounding Williams's death, confirmed he had been a resident at the Sirhowy Arms hostel, which houses vulnerable and homeless people, including ex-offenders.
It was there on Thursday that a lone female officer who was sent to the scene found him attacking Ms Yemm, from Blackwood.
Sources confirmed Ms Yemm suffered substantial facial injuries in the attack on 6 November.
The murder was described as the "the stuff of nightmares" by William Graham, a Conservative assembly member for South Wales East, who has called for a wide ranging inquiry.
A woman murdered in an act of cannibalism has been remembered in prayers at a church service.