A former Latvian detective has told how he fears the worst for missing Alice Gross after learning wife killer Arnis Zalkalns was prime suspect in her disappearance.
The retired police officer warned the 41-year-old, who stabbed Rudite Zalkalns to death in 1997 and dumped her body in a shallow grave, could strike again.
And he said the murder was so brutal it still haunts him to this day.
He spoke to the Mirror as it was claimed the missing builder was accused of drugging a girl of 14 before allegedly sexually abusing her in London five years ago.
Scotland Yard are still hunting for Zalkalns who vanished on September 3 – a week after Alice, 14, disappeared.
The search has now spread to Latvia, where there was a reported sighting of him on the island of Kundzinsala.
The retired officer, who investigated Rudite's murder, said: "My blood ran cold when I heard that he was a prime suspect in another case.
"I've investigated many murder cases in my career but this was the most callous case I've ever come across. It has stayed with me all my life. I have had sleepless nights since he has been connected to this young British girl's disappearance.
"I would suggest that the British police look for a shovel and a knife near where this little girl went missing. Also they should check for objects near where this man works or lives. This man made me sick.
"During his police interview, sometimes he cried, sometimes he got agitated and sometimes he had violent mood swings. But he never showed any remorse. He always said, 'She deserved it.' And now this man has come back to haunt us.
"I am now retired but I am ready to go back to work if the British police need my help. That is how worried I am. I think he has come back to Latvia. It's easy to get back here.
"There are lots of people who would harbour him. I feel very sorry for all the women who have ever become involved with him. I don't understand how he has managed to charm them to the extent that some of them may even protect him now.
"This case will stay with me for the rest of my life, it was really gruesome."
Rudite's body was found in a forest just outside of the Latvian capital Riga where she lived with Zalkalns and their child Elvira, now 19. She had been dug up by animals and ripped apart. He was jailed for seven years.
It was believed officials knew nothing of the murder when he arrived in Britain in 2007. He was later accused of sexually assaulting the teenager in London and quizzed by police. No charges were brought because it was believed the youngster would not co-operate with police. But his former partner Liga Rubezniece said he told her he had been trying to help the girl as she was drunk.
The 34-year-old, from Liepaja – where Zalkalns moved after being freed – said: "He told me he saw her crawling across the street drunk when he went over to help her.
"He said he was worried about her being knocked over. He picked her up and walked her to the side of the road. He says he gave her his mobile phone to ring her parents but instead she rang the police. She told officers she had been drugged and attacked by him. I don't believe this. He was investigated by police and they closed the case."
Liga insisted her ex was a "good father" to their two young children in Latvia and would send 133 euros over from the UK once a fortnight to help support them. His last payment was due on September 14 but it never arrived in her account.
She added: "He is not a monster and he has never hurt me in any way. And I can say that he doesn't have an interest in young girls. He raised my oldest daughter."
The hunt for Alice is the largest Met search operation since the 7/7 bombings in 2005 , police said. She was last seen walking along a canal tow path on August 28 near her home in Hanwell, West London.
Zalkalns, of nearby Ealing, was spotted riding his bike down the same stretch 15 minutes later. He vanished when police announced the case had become a murder hunt.
Zalkalns has not accessed his bank accounts since and left his passport at home where he lives with his partner Katerina Laiblova and their one-year-old daughter.
A Latvian police source said: "We have been asked by the British police to start searching for Arnis Zalkalns. There is a possibility he might have fled here."
A comment on a Latvian website reporting his disappearance read: "Look in Kundzinsala."
A former landlord of Zalkalns who has a house in Boston Manor where the suspect lived with Katerina told how the couple "kept themselves to themselves".
Radoslav Andric, 64, said: "He was nice at first but became very aggressive."
Police today combed a railway embankment on a little used line near where Alice vanished.
