A seven-year-old boy involved in a beach tragedy that killed his teenage cousin and her mother has died in hospital, his family has said.

Musa Ahmed was on a day trip to West Mersea, Essex, on 22 July, when he and five relatives got into difficulty in the water.

While he was pulled from the water and airlifted to hospital, Shelina Rahman, 41, and 15-year-old Sameeha, died at the scene.

Musa’s family said he died “in a state of ease and peace” at the Royal London Hospital on Tuesday evening.

The family had travelled to the island, near Colchester, from Ilford in east London that morning.

Three others were also taken to hospital by ambulance after the incident, first reported to Essex Police at 17:35 BST, and were said by the force to be “recovering”.

Musa’s father, Shahin Ahmed, has said they were swept away by a “very strong” tide and police said they made “significant efforts to help each other”.

In a statement, the family also thanked doctors and nurses at the hospital’s intensive care unit who “demonstrated outstanding care and dignity”.

“We would also like to thank the whole community for their support and prayers,” they added.

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Det Ch Insp Al Pitcher, who is leading the investigation, also said “all our thoughts are with the family and friends of those involved”.

“Their bravery and strength has been humbling,” he added.

His team has been speaking to witnesses as they try to build a picture of how the tragedy unfolded.

Bystanders – including Craig Bowe, who made three rescue attempts – sprung into action as the tragedy unfolded, administering CPR to the Rahmans.

Bowe managed to help Musa on to a lifeboat, as well as another boy, but said Musa was “not in a good way”.

The incident has prompted calls for extra safety measures on the beach, including signage and life jackets.

Colchester City Council and West Mersea Town Council have both said warning signs are due to be installed.