The Duchess of Sussex’s half brother Thomas Markle Jr has been named as a “person of interest” in child sexual abuse image allegations facing Meghan’s father.

The Philippines’ interior and local government secretary Jonvic Remulla told a press conference in Manila there are “signs that point that the son is involved in the crime as well”.

But he said Mr Markle Jr, who alerted local police and the FBI to images he found in his father Thomas Markle Snr’s belongings, was not yet being treated as a suspect.

More than 7,000 photos and one video – all of under-age males and females of Asian, Latin and European descent, with some as young as 10 and 11 – were uncovered, Mr Remulla said.

He described the images as “the most deplorable displays of impunity towards sexual activity that I have ever seen”.

Mr Markle Snr, who is estranged from Meghan, has been moved into a care home for dementia patients, prompting fears the FBI will not be able to interview him.

Mr Remulla said: “We’re determining if son is involved… There are signs that point that the son is involved in the crime as well but only as a person of interest so far.”

He added: “We will know in the next few days.”

Mr Markle Sr, who returned to the US in May, has admitted paying for sex in the Philippines but denied possessing child abuse imagery.

Mr Remulla said Mr Markle Jr was still in Cebu City.

Meghan was “deeply distressed” by the allegations and revealed she was sent a letter via the Metropolitan Police and Royalty and Specialist Protection seven years ago.