The mystery of the horticulturalists missing in South Africa

South African police are asking the public for help in finding a missing couple who were kidnapped last month in a case with suspected links to the Islamic State group (IS).

Rodney Saunders, 73, and his wife Rachel, 64, have dual South African and British citizenship.

Three suspects have been remanded in custody, and appeared briefly on Thursday in a small courtroom near the port city of Durban.

"We're looking for anything helpful from the public," said Captain Lloyd Ramovha, spokesman for the elite police unit, the Hawks.

The case has led the British Foreign Office to update its warning about the threat of a terrorist attack in the country, which has upset many South Africans.

What do we know?

The Saunders, horticulturalists who run a seed business in Cape Town, were reported missing a fortnight ago.

They had been travelling in a remote region of KwaZulu-Natal.

The BBC has declined to comment on reports that, shortly before they were kidnapped, they had been working with a film crew from the television programme Gardeners' World, looking for rare plants.

The couple's blood-stained car was later found abandoned near Durban. Tens of thousands of pounds have reportedly been drained from their bank accounts.

Who are the suspects?

Fatima Patel, 27, and Saffydeen Aslam del Vecchio, 38, - who were already under police surveillance - were arrested a fortnight ago.

Ms Patel had previously been arrested, with her brother, in 2016 during a separate anti-terrorism raid closer to Johannesburg. Neither of them were charged.

The pair now detained face charges of kidnapping, aggravated robbery, and contravention of anti-terrorism laws. Another suspect, 19-year-old Themba Xulu, was arrested this week and is facing kidnapping and burglary charges.

Is IS active in South Africa?

There have been no known attacks by IS, or any other jihadist group, in South Africa.

The most prominent case linked to the Islamic State group in South Africa involves the Thulsie twins, Brandon-Lee and Tony-Lee, who were arrested during the 2016 raids that also saw Fatima Patel detained.

The twins are due to face trial on 12 terrorism charges, related to alleged plans to attack Jewish targets and the US embassy in South Africa.

In recent years dozens of South African citizens are thought to have travelled to the Middle East to join IS, with many returning home.

The British Foreign Office has cited those returnees as potential security threats, but South Africa is generally not seen as fertile ground for extremism.

Experts have rather warned that the country could be used by militants from other African countries looking to secure travel documents or simply to lie low.

Why did the Foreign Office issue a warning?

The British Foreign Office website had already warned that "terrorists are likely to try to carry out attacks in South Africa".

This advice was updated immediately after the kidnapping was reported, linking the kidnapping to the threat "from extremists linked to Daesh (formerly referred to as ISIL)" - two other names used for the Islamic State group.

The South African authorities and some security experts here say the amended travel advisory is unnecessary, or even "alarmist," and the risk from terrorism in the country is negligible.

But Britain has declined to change its advice to travellers.

Read more:

The rise and fall of 'Islamic State'

‘Islamic State’ around the world

More about South Africa