A HULKING monster known as the “Frankenstein” killer struck fear into the heart of the Royal Navy in the 1990s as he targeted sailors to butcher in a depraved reign of terror.
Allan Grimson lured two young recruits back to his flat in Portsmouth then brutally murdered them when they spurned his advances.
He first slaughtered Nicholas Wright, 18, on December 12, 1997 – before murdering Sion Jenkins, 20, exactly 12 months later.
The former petty officer – dubbed the “Royal Navy‘s Dennis Nilsen” – is feared to have killed up to 20 people – including missing sailor Simon Parkes.
He was last seen in December 1986 when the ship he was serving on with Grimson, HMS Illustrious, was docked in Gibraltar.
Now 38 years later, police are searching a car park in the territory for Simon after receiving fresh information.
Excavation work led by Hampshire and Isle of Wight Constabulary is ongoing at the site and follows similar digs in Gibraltar.
Radio operator Simon was just 18 when he vanished after going on to shore.
A huge manhunt was launched after he failed to make it back to his ship but there has been no trace of the teen since.
His disappearance remained a mystery until ten years later when police showed up at mum Margaret’s home as part of an ongoing investigation into Grimson’s evil crimes.
Officers revealed the double killer had been on the HMS Illustrious with Simon and was last seen alive in a bar with him on the night he vanished.
Chillingly, the final sighting was on December 12 – the exact date his previous victims were slaughtered.
Horrific details then emerged over the monster’s twisted crimes after he first targeted Nicholas.
The 18-year-old was bludgeoned with a baseball bat after he rejected Grimson’s sexual advances before his ear was sliced off with a diving knife.
Once Nicholas was too hurt to defend himself, the brute slit his throat.
The next day, Grimson wrapped his body up while naked – later telling police he’d felt a “tingling” sensation while doing so.
He then dumped the naval rating’s mutilated body in a ditch.
Exactly one year later, Grimson attacked and raped Sion in his house of horrors before tying him up and putting him in a bathtub.
As the 20-year-old begged to go home, the killer beat him to death with a bat before dumping his body by the side of the A32.
Grimson confessed to his sadistic crimes in excruciating detail – leading one expert to brand him the most dangerous psychopath of the 250 he had examined.
He was jailed in 2001 at Winchester Crown Court for life with a minimum of 22 years.
Sentencing, Mr Justice Cresswell told him: “You are a serial killer in nature if not in number.
“You are a highly dangerous serial killer who killed two young men in horrifying circumstances.”
In November it emerged Grimson could be back on the streets in weeks after a parole hearing was set for next month.
The monster has continued to deny his involvement with Simon’s disappearance.
Margaret, now aged 81, is hoping the latest search will finally bring her some closure after an agonising wait for answers.
She also told how she believes Grimson should remain behind bars.
The mum said: “I would be devastated if he came out of prison. I am 99 per cent sure he killed Simon. I think he’s a very dangerous man.
“I do not think he will change his ways, he’ll be a dangerous man forever.”
The latest search is being carried out after a “further potential area of interest” was identified to police.
Last August, officers excavated the Town Range car park and have previously dug in a cemetery.
A spokesperson for the force said: “A working group led by Hampshire and Isle of Wight Constabulary, comprised of detectives and specially trained search officers both from the police and military, will be carrying out the work in Gibraltar during the week of 15 January as we continue to investigate what happened to Simon Parkes.
“The operational activity is part of our work to assess a new line of enquiry that has been presented to us.
“This investigation continues to be a collaborative operation between Hampshire & Isle of Wight Constabulary and Royal Gibraltar Police with support from the Ministry of Defence.”
