A six-year-old girl who was pulled from the sea at Shoreham on Tuesday along with three of her family members has died in hospital.

Saja El-Khawas got into difficulty in the water alongside her 14-year-old sister Sara El-Khawas, and her parents Hassan El-Khawas, 55, and Zeina Alayn, 37, who died earlier this week. Saja had been in hospital in a critical condition since the incident.

Her identity and death were confirmed in a legal notice from solicitors acting on behalf of Guy’s and St Thomas’ NHS Foundation Trust, as well as the Palestinian Forum in Britain.

The Palestinian embassy said Mr El-Khawas was a Palestinian refugee from the Rashidieh Camp in Lebanon.

Police previously said it is believed the family had travelled down from London to visit Shoreham, and that they had entered the sea for a swim.

On Wednesday, Sussex Police said their investigation remains open, but after a review of CCTV footage and initial witness accounts, it is currently thought the deaths were a tragic accident, with no third-party involvement.

Chief Superintendent James Collis said: “The events of Tuesday afternoon are a heartbreaking tragedy which has devastated a family and their friends and had a profound impact on the Shoreham community.”

Sara’s school paid tribute to her earlier this week following news of the 14-year-old’s death.

The Ellen Wilkinson School for Girls in Ealing, west London, wrote in a statement: “Sara was a sweet girl, well-liked by staff and students, and she will be greatly missed”.

“Our thoughts and heartfelt condolences are with her family, friends, and all those affected. We are also thinking of her sister and loved ones at this extremely difficult time.”

The Palestinian Forum in Britain previously wrote on social media: “The (PFB) extends its deepest condolences to the family of Hossam El-Khawas, his wife and daughter, and to the Palestinian community in Britain, especially the people of Rashidieh Camp, Lebanon.

“May Allah have mercy on them and grant strength and patience to their loved ones.”

Rashidieh Camp is on the Mediterranean coast in southern Lebanon and is one of the most populous Palestinian refugee camps in the country.

Andy Burnham called the deaths a “tragedy” as he issued a reminder about open water swimming during the heatwaves. The prime minister said on Wednesday: “The thing I can say today – and there is still, I think, a further heatwave to come in this summer period – is just to remind people about the dangers of open water swimming.

“The coldness, even when it feels hot outside, it can shock people and that can cause the difficulties. So people just need to remember that at all times.”