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
