Three Nigerian sisters who drowned in the sea off Brighton, southern England, have been ruled to have taken their own lives following an inquest into their deaths.

The sisters, Jane Adetoro, 36, Christina Walters, 32, and Rebecca Walters, 31, lived together in Greenford, west London. They had become increasingly withdrawn following the death of their mother in 2010.

The inquest heard that the sisters visited an area of Birmingham close to where their mother died on May 11 before travelling to Brighton the following day.

According to BBC, they were later seen on the town’s eastern seafront in the early hours of May 13, when they entered the sea in difficult conditions. None of the sisters could swim.

Their father, Joseph Jacobsen, described the loss of his three daughters as heartbreaking.

Coroner Penelope Schofield said the court could not speculate on the reasons behind the sisters’ actions.

Evidence presented at the inquest showed that a taxi carrying the sisters arrived in Brighton at 10.21pm on May 12. The driver reportedly noticed that they were quiet during the journey.

Closed-circuit television footage later showed the sisters on Brighton’s eastern seafront. They were last seen alive at 2.42am on May 13.

The inquest also heard that police examining Christina’s laptop found 227 references to water and 179 references to suicide. Christina had reportedly experienced anxiety and depression following their mother’s death.

Rebecca’s medical records contained no significant information relevant to the inquest, while Jane was not registered with a doctor.

Toxicology tests found no evidence of drugs or alcohol in the sisters’ systems, and investigators found no evidence of violence.

Jane was brought ashore by the Royal National Lifeboat Institution (RNLI) and pronounced dead. Christina was recovered by an RNLI lifeboat, while Rebecca’s body was later washed ashore. Both were pronounced dead by paramedics.

The inquest examined the circumstances surrounding the deaths and the sisters’ movements in the hours before they entered the water. Vanguard