On 5 January, aristocrat Constance Marten, her sex offender partner Mark Gordon and their newborn baby went missing, abandoning a broken-down car, which was later found in flames, on the M61 near Bolton.
Since then, the trio have been traced to Sussex, where they were last spotted on 12 January, but have since avoided detection.
The Metropolitan Police is offering a £10,000 reward for information that leads to them being found safe.
Here are 11 facts about the case.
1. Marten’s royal links
Marten, 35, comes from an aristocratic family.
Her grandparents were Toby Marten, a Lieutenant Commander in the Royal Navy, and his wife Mary Anna, who attended the Brownies pack at Buckingham Palace alongside Princess Margaret in her youth and was the goddaughter of the late Queen Mother. Her father was a Page to the late Queen.
2. Her rapist partner
Her partner Gordon, 48, who it is understood she met in 2016, was jailed in the late 1980s in Florida, US, after raping and assaulting a woman when he was 14. After serving a 20-year sentence he was deported back to the UK in 2010.
3. Their relationship
Marten has been estranged from her family since beginning the relationship with Gordon.
The pair were thought to have previosuly lived together in Ilford.
From around September last year they began living in a series of AirBnBs around the country on short lets and amassed cash to enable them to live off-grid and avoid the attention of the authorities.
4. Timeline of their disappearance
Having abandoned their car in Bolton on 5 January, Marten and Gordon hailed a taxi to Liverpool where they took another taxi to Harwich in Essex, arriving just after midnight on Friday 6 January.
Police said they were also spotted in Harwich before travelling to Colchester then taking a taxi to East Ham station.
Detectives have since established that the couple took a taxi from East Ham, being dropped off in Whitechapel Road at 6:14pm on 12 January where Gordon was spotted leaving an Argos after purchasing a tent.
At 11.46pm they got a taxi to Haringey then another to Newhaven, East Sussex, where they were last seen walking along Cantercrow Hill into the fields beyond on 12 January.
5. What the pair are carrying
While the fire in the car destroyed most of their abandoned belongings, the pair are understood to be in possession of a substantial amount of money, with their taxi journeys being paid in cash amounting to several hundreds of pounds.
6. Marten’s motivations
A friend of Marten has spoken out about the case, claiming the aristocrat was allegedly “brainwashed” by an encounter with a controversial Nigerian preacher.
Marten allegedly got involved with the teachings of T.B. Joshua, a leader of a Nigerian megachurch.“She ended up becoming one of his disciples in Nigeria. I believe she got brainwashed while she was over there. The experience traumatised her,” the unnamed friend claimed.
“She was not the same person when she came back. She always used to be wild, but also happy, kind and buoyant. She was darker when she came back and she found things more difficult.
“She never told us what really happened. T.B. Joshua was a God-like figure. It was scary, and I believe it changed her. It was a huge part of her life.”
7. The investigation
More than 100 officers are involved in the investigation and have more than 223 CCTV hours with assistance from the National Crime Agency.
The police are offering a £10,000 reward for information that leads to them being found safe.
8. Marten’s father’s emotional plea
On 19 January, Marten’s father, Napier Marten issued an appeal to his estranged daughter in the Independent.
“Darling Constance even though we remain estranged at the moment, I stand by, as I have always done and as the family has always done, to do whatever is necessary for your safe return to us,” he saiid.
“I beseech you to find a way to turn yourself and your wee one in to the police as soon as possible, so you and he or she can be protected. Only then can a process of healing and recovery begin, however long it may take, however difficult it may be.
He added: “I want you to understand that you are much much loved whatever the circumstances. We are deeply concerned for your and your baby’s welfare”.
9. Marten’s mother’s emotional plea
In February, Marten’s mother also issued an open letter saying she wanted to “help” her daughter.
“I want to help you and my grandchild,” she wrote. “You deserve the opportunity to build a new life, establish a stable family and enjoy the same freedoms that most of us have.
“Constance, I will do what I can to stand alongside you and my grandchild. You are not alone in this situation. We will support you in whatever way we can.
“I am ready to do what it takes for you to recover from this awful experience so you can thrive and enjoy motherhood.
“I love you and miss you, Mum xx.”
10. What the police have said
Detective Superintendent Lewis Basford, who is leading the investigation, said: “We are extremely concerned that a newborn baby – less than a week old at the time on 7 January – has been exposed to sub-freezing cold temperatures if Mark and Constance have been camping out somewhere as our evidence suggests.
“No child, especially a tiny, newborn baby, should be forced to endure such dangerous, potentially life-threatening, conditions.
He added: “There is nothing to suggest that any of them have come to any sort of intentional harm – we just need to ensure they are OK, especially the baby, and do not require any medical assistance for any underlying issues.”
11. How to help
Anyone who has information on the family’s whereabouts should call the incident room on 020 7175 0785.
Alternatively, information can be reported 100 per cent anonymously to the independent charity Crimestoppers on 0800 555 111. They never ask for personal details and they do not trace your device.
