LONDON, United Kingdom (AFP) — A hospital electrician in Britain pleaded guilty Thursday to murdering then sexually assaulting two women in 1987 before, decades later, carrying out scores of sex attacks on corpses in mortuaries.

David Fuller admitted strangling 25-year-old Wendy Knell and Caroline Pierce, 20, in two separate attacks months apart in Kent, southeast England, prosecutors said.

The 67-year-old was only arrested last December and, four days into his trial on Thursday, changed his pleas after initially pleading not guilty on the grounds of diminished responsibility.

During this week’s court proceedings, it was revealed Fuller went on to sexually assault at least 99 women and girls in hospital mortuaries where he was working as an electrician.

His victims included three children under the age of 18 and others older than 85 between 2008 and 2020.

Police who searched his home last year found he had filmed himself carrying out the attacks at the two mortuaries where he had worked in electrical maintenance roles since 1989.

Officers only discovered his crimes after Fuller was arrested for the 1987 murders following a DNA breakthrough.

Ahead of trial for the twin killings, Fuller admitted 51 other offences, including 44 charges relating to 78 identified victims in mortuaries, according to the Crown Prosecution Service,  which brings prosecutions in England and Wales.

Investigators have so far detected 99 potential victims, of which they know the names of 78.

The offences include the sexual penetration of a corpse, possessing an extreme pornographic image involving sexual interference with a corpse and taking indecent images of children.

The evidence found dates back to 2008 — when digital camera devices were becoming more widespread — but police believe the true scale of his offending may never be known.

Senior CPS prosecutor Libby Clark said the extent of his necrophilia crimes appeared unprecedented.

“I have never come across anything like it — the numbers, the nature of offending — and I don’t know anybody who has, be they police or other prosecutors,” she said.

“This was a man with a very, very dark secret.”

Police leaders tasked more than 150 specialist family liaison officers with visiting the victims’ families, while some £1.5 million ($2.0 million, 1.75 million euros) has been earmarked to pay for bespoke support.

Health Secretary Sajid Javid said he had asked the health sector to review mortuary and post-mortem access in light of the findings.

Home Secretary Priti Patel, whose brief includes the police, called the case “shocking”. 

“My heartfelt sympathies go out to the families of all those who may have been affected,” she said.

“The sickening nature of the crimes committed will understandably cause public revulsion and concern,” she added.

An independently chaired review is already underway into exactly what occurred at the health body in Kent where the crimes occurred, he noted. 

Fuller will be sentenced at a later date.