Liam Poole, of Burgess Hill in West Sussex, disappeared with his 46-year-old father Daniel on April 1 after leaving their luggage and passport in their hotel.

Liam's grandmother, Kathy Catney, went to Spain with the BBC's Inside Out programme and visited the golf resort where the two men stayed.

She told the programme that her grandson did not play golf and his numerous visits to the region made her suspicious.

Liam Poole, of Burgess Hill in West Sussex, disappeared with his 46-year-old father Daniel on April 1 after leaving their luggage and passport in their hotel. Picture: PA

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After the pair disappeared, Ms Catney said the family were contacted via a phone message from Morocco asking for a ransom of £100,000.

The money was raised in hours, but there was no follow-up phone call or demand.

While in Estepona, Ms Catney visited bars and asked them to display posters featuring photos of the missing men.

She was rebuffed by one business.

"The barman, when I showed him the poster, he said he'd seen them and that they were both 'wrong 'uns', and that just upset me," she said.

Ms Catney said she wants to know the fate of her eldest grandson and asked anyone with information to contact the authorities.

"I do think Liam's died - I think he's been killed.

"Where? I hope he's not at the bottom of the sea ... because I want the chance of someone giving me him back."

British and Spanish police continue to investigate the disappearance of the two men.

Members of the public can report information online or by calling 101 quoting Operation Pheasant.

Grandmother fears for grandson missing in Spain