COLOMBO, Sri Lanka (AP) — Maldives police said Sunday they arrested a person believed to be the prime suspect in an explosion that critically wounded the country’s former president and which was blamed on Muslim extremists.

Police said they now have three of four suspects in custody. Thursday’s blast targeted Mohamed Nasheed, currently the speaker of Parliament, who is recovering in a hospital after multiple surgeries.

Police did not give details on the latest suspect or his background, but in a text message confirmed that they believe he is the person whose pictures were released Saturday as authorities sought public assistance identifying him. The fourth suspect remains at large.

Officials blamed Islamic extremists for the attack, although investigators still don’t know which group was responsible. Two of Nasheed’s bodyguards and two apparent bystanders, including a British citizen, were also wounded.

Nasheed has been an outspoken critic of religious extremism in the predominantly Sunni Muslim nation, where preaching and practicing other faiths are banned by law. He has been criticized by religious hard-liners for his closeness to the West and liberal policies.

Hospital officials said Nasheed, 53, remains in an intensive care unit after initial life-saving surgeries to his head, chest, abdomen and limbs. A relative tweeted early Sunday that Nasheed had been able to have long conversations with some family members.

Shrapnel from the blast damaged Nasheed’s intestines and liver, and a piece of shrapnel broke his rib and had been less than a centimeter from his heart, hospital officials said.

Officers from the Australian Federal Police were assisting with the investigation, following a request from the Maldives. A British investigator was also set to arrive in the Indian Ocean archipelago on Sunday.

Nasheed was the first democratically elected president of the Maldives, serving from 2008 to 2012, when he resigned amid protests. He was defeated in the subsequent presidential election, and was ineligible for the 2018 race due to a prison sentence, but has remained an influential political figure.

He has championed global efforts to fight climate change, particularly warning that rising seas caused by global warming threaten the archipelago nation’s low-lying islands.

The Maldives is known for its luxury resorts but has experienced occasional violent attacks. In 2007, a blast in a park in the capital wounded 12 foreign tourists, and was also blamed on religious extremists.

The Maldives has one of the highest per capita numbers of militants who fought in Syria and Iraq alongside the Islamic State group.

Authorities announced in January that eight people arrested in November were found to have been planning to attack a school and were in the process of building bombs in a boat at sea. Police said the suspects conducted military training on uninhabited islands and recruited children.