The 20 year old midwifery student was murdered by Shofah El-Israel, whose birth name is Ajibola Shogbamimu, and he has been sentenced to 17 years.
He also attended the closed and strict community at Israel United in Christ Church, where they believe that black people are the natural 12 tribes of Israel.
He was convicted of murder despite Joy's body never being found.
In a video appealing to anyone who might know or stumble across information, Detective Superintendent Jo Walker, Head of the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit, explained the unique challenges of investigating cases where the absence of a body means that forensic opportunity is reduced.
Det Supt Walker said: "She had a life with the church, she had friends, she had family and there were events that Joy had planned.
"If she were alive there are things that she would still be doing."
She added: "We really would like to find Joy's body - somebody out there, somewhere, we hope has some information, however small that may be, that could help lead us to Joy's body. I would urge anyone who has information or thinks they remember anything back from those dates that would help us, please contact us."
"We've got a family that are without their daughter's body. I would urge anyone that's got any information to please come forward and help us find Joy's body and get her back to her family."
You can report information online at herts.police.uk/report or stay 100% anonymous by contacting the independent charity Crimestoppers on 0800 555 111 or via their untraceable online form at crimestoppers-uk.org.
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