Steeltown Murders: How a DNA-first caught a serial killer 30 years on

Three 16-year-old girls strangled, a country's biggest execution hunt and the ground-breaking mode constabulary recovered the serial slayer - this is the existent beingness communicative down the BBC's latest drama.

Many feared detectives would ne'er find the slayer known arsenic the "Saturday Night Strangler" - but 30 years on, helium was recovered successful the astir improbable place.

It took 2 DNA-firsts to find the antheral who had struck fearfulness into southbound Wales.

The communicative of calamity and justness is down the caller play Steeltown Murders.

It each started successful the summertime of 1973, erstwhile the metropolis and surrounding areas of Swansea were shocked by 2 incidents of girls going retired partying but not returning home.

In July, 16-year-old Sandra Newton had been retired with her fellow successful adjacent Briton Ferry erstwhile she disappeared connected her five-mile locomotion location astatine astir 1 o'clock successful the morning.

Police believed she had tried to hitchhike her mode home.

Sandra's assemblage was recovered 2 days aboriginal successful a culvert. She had been deed implicit the caput and strangled with her ain skirt.

Then, successful September, Geraldine Hughes and Pauline Floyd were recovered dormant successful woodland successful adjacent Llandarcy aft hitchhiking their mode location from a nighttime retired successful Swansea.

The 16-year-old champion friends had been beaten, raped and strangled, and their bodies dumped conscionable 7 miles from wherever Sandra was found.

Their deaths sparked Wales' biggest execution hunt and a squad of 150 officers questioned 35,000 radical who loosely fitted the statement of the past idiosyncratic seen with Geraldine and Pauline.

But having bushy hair, a moustache and being a antheral betwixt 30 and 35 years of property was not the lone pb for investigators - detectives besides had a statement of the car helium had been driving.

Their cardinal witnesser had seen the girls leaving Swansea that night, getting into a airy coloured Morris 1100 being driven by a man.

As a BBC reporter, I helped to screen these killings backmost successful 1973.

They stunned an country wherever murders seldom happened.

The daze of young girls going retired for amusive and ne'er getting location created a existent consciousness of fearfulness - and this antheral was inactive astatine large.

There was a tremendous outpouring of grief. The communities were hopeless for idiosyncratic to beryllium caught - but no-one was arrested and determination were nary beardown leads.

There were truthful galore areas wherever the slayer could person travel from.

Working without computers, constabulary faced an intolerable task arsenic they sifted done a immense excavation of imaginable suspects from a upland of paperwork.

Officers, astatine the time, considered that the aforesaid idiosyncratic had killed each 3 girls - but idiosyncratic was already successful the framework for Sandra's murder.

The premier fishy for Sandra's decease was the past idiosyncratic who saw her. That was her boyfriend, but helium maintained his innocence and was ne'er charged.

Despite the brutal similarities, detectives continued to tally abstracted inquiries into Sandra's decease and the murders of Geraldine and Pauline - until astir 30 years later.

Both investigations were linked successful the aboriginal 2000s by an emerging crime-solving tool, erstwhile South Wales Police started reopening acold cases hoping DNA could yet bring killers to justice.

Firstly, semen stains connected Geraldine and Pauline's covering were isolated to amusement they matched that of the aforesaid antheral - but the idiosyncratic was not connected the precocious opened DNA database.

But a twelvemonth into the caller Operation Magnum inquiry, tests connected Sandra's underwear gave detectives their archetypal large breakthrough.

There was DNA contiguous from an chartless male.

"I recognised consecutive distant from a peculiar diagnostic of the DNA - this was the Llandarcy killer," said forensic idiosyncratic Dr Colin Dark.

"This was an implicit bombshell due to the fact that this meant determination was a serial slayer operating successful southbound Wales successful 1973 sidesplitting young girls."

The breakthrough besides categorically proved Sandra's aged fellow astatine the clip of her decease was wholly innocent.

"This was the archetypal clip successful astir 30 years we knew that the aforesaid antheral had killed each 3 girls," said the antheral that led the caller investigation, Det Insp Paul Bethell.

Because determination was nary matching illustration connected the nationalist database, the killer's individuality inactive remained a enigma and detectives asked BBC Crimewatch for help.

But scientists had travel up with different trailblazing mode of utilizing DNA to drawback the murderer.

"We started to deliberation was it imaginable that we could usage the thought that transgression tin tally successful families," said Dr Dark, whose squad was continually checking the illustration with caller profiles connected the ever-growing DNA database.

"You inherit your DNA from your parents and you walk your DNA onto a child. So could we look connected the DNA database for a kid of the offender? This was a definite possibility."

Dr Dark said that meant "getting a spreadsheet printout of respective 1000 DNA profiles from men successful the southbound Wales area, sitting down with a pencil and a ruler and crossing retired everyone that doesn't match."

"After respective hours of going done the process, we were near with astir 100 names. They were each nonstop fractional matches to the offender's profile. So they were perchance children of the offender," helium said.

"This was a crushed breaking technique, the archetypal clip it's ever been done successful the UK and perchance the satellite - and from there, the caller investigative instrumentality present known arsenic familial DNA was developed."

Meanwhile, detectives had painstakingly whittled down the database of 35,000 imaginable killers to conscionable 500 premier suspects.

"Our shortlist was based connected the statement of the individual, did the proprietor person a 1100 car and did they person erstwhile convictions for unit oregon intersexual offences," recalled Det Insp Bethell.

After transverse referencing some lists, 1 surname stood retired - Kappen.

Local car thief Paul Kappen's DNA was connected the database aft committing offences successful and astir the Port Talbot area, but helium was lone 7 astatine the clip of the murders.

His dad, however, had been questioned backmost successful 1973 due to the fact that helium fitted the statement of the wanted antheral - and drove a light-coloured Morris 1100.

That aforesaid year, constabulary visited nightclub bouncer and part-time autobus operator Joseph (Joe) Kappen's location connected Port Talbot's Sandfields assembly estate.

But helium had an alibi from his woman and claimed his car was breached down connected the nighttime of the murders.

"He was known successful the assemblage arsenic a spot of a thug," recalled Det Ch Insp Bethell.

"He had a past of home unit and had been to situation connected a fig of occasions."

Now, with his son's DNA proving helium was a 50% lucifer of the killer's DNA, Joseph Kappen became the premier fishy - decades aft the murders.

But determination was a occupation getting a DNA swab from him erstwhile they knocked connected his door.

Kappen had died of lung crab 11 years earlier successful 1990, aged 48.

To corroborate constabulary suspicions, scientists requested DNA swabs from Kappen's ex-wife and girl to comparison them to the killer's sample.

"That gave america two-thirds of a afloat illustration for Joe Kappen," said Dr Dark, whose squad were based astatine the aged forensic laboratory successful Chepstow, Monmouthshire.

"When we compared that to the transgression stain profile, we could spot that matched - but we needed the afloat illustration to marque perfectly definite that we had identified the killer."

Detectives were determined to beryllium perfectly definite that Kappen was the slayer truthful the families of the 3 girls could person immoderate benignant of closure.

That meant exhuming Kappen's body, which would beryllium the archetypal clip that a fishy would beryllium exhumed successful the UK to beryllium guilt.

Detectives needed to spell to the apical for support and question the location secretary's approval.

"My main interest was whether determination was capable grounds due to the fact that it is simply a large measurement arsenic if you get it wrong, the families progressive would rightly beryllium aggrieved," said Lord Blunkett, location caput betwixt 2001 and 2004.

"My determination was precise wide that Joseph Kappen's assemblage should beryllium exhumed to trial erstwhile and for each that this was the antheral who committed the murders and bring immoderate comfortableness we could to the families. For the involvement of everyone, uncovering the information was truly important."

So past was made successful May 2002, erstwhile exhumation of the three-person sedate began connected the changeable of midnight.

"It was a horrible nighttime and conscionable arsenic we got to Kappen's coffin, determination was a clap of thunder," recalled Dr Dark.

"It was the feeling that evil had been identified, it sent shivers down my spine."

Forensic DNA introspection astatine adjacent Morrison infirmary successful Swansea proved Kappen was the slayer of each 3 girls, aft astir 3 decades.

"No words tin picture the mode we each felt, it was a immense relief," said Geraldine's cousin, Julie Begley.

"None of america ever stopped hoping that 1 time we would find retired who helium was. Although you get connected with your life, it ne'er goes away.

"Geraldine was a fantastic girl. She was ever afloat of fun."

It was not conscionable closure for Geraldine and Pauline's loved ones, but for Sandra's household and adjacent friends too.

"I've been going down to her sedate for 49 years and it's hard to judge she's there," said Sandra's person Theresa May.

"My beauteous friend. She had her beingness taken distant from her, her aboriginal taken distant from her.

"I inactive deliberation astir her now. All these things that we could person and should person done together.

"But aft each of those years, she tin yet remainder successful bid now."

Philip Glenister and Steffan Rhodri play the detectives starring the acold lawsuit execution investigation, utilizing trailblazing DNA techniques to effort to drawback the slayer aft astir 30 years.

The four-part play and accompanying documentary starts connected Monday connected BBC One and volition beryllium disposable arsenic a container acceptable connected BBC iPlayer.