Catholic priests and nuns carry photos at St Sebastian's Church in Negombo on April 21 this year as they pay tribute to the victims killed in the 2019 Easter Sunday bombings. Photo: AFP / Lakruwan Wanniarachchi

Sri Lankan prosecutors Monday indicted the alleged mastermind of the 2019 Easter Sunday suicide bombings along with 24 men they say were co-conspirators in the island’s worst single terror attack.

Almost three hundred people including dozens of foreign nationals were killed in the April 21 attacks on three churches and three luxury hotels, in a wave of killings targeting Sri Lanka’s Christian community.

Prosecutors have brought over 20,000 charges against the suspects, three of whom have already been accused of terrorism by the US Justice Department.

The suspects are in police custody, but one of them did not appear in court Monday as he was suffering from Covid-19, officials said, adding that hearings will begin on November 23.

Prosecutors told the court that US and Australian forensic experts assisted investigators in tracking down the backers of the eight-member suicide squad responsible for the attacks.

Sri Lanka authorities have accused their ringleader, Mohamed Naufar, of being the mastermind of the deadly suicide bombings and of being a member of the Islamic State group.

Former police chief Pujith Jayasundara and top defense official Hemasiri Fernando are also being prosecuted separately for failing to act on repeated intelligence warnings of a possible IS attack.

An inquiry set up by former president Maithripala Sirisena found that he too was responsible for failing to prevent the attack and should be prosecuted.

The head of the Catholic church in Sri Lanka, Cardinal Malcolm Ranjith, has repeatedly said he is unhappy with the lack of progress in the inquiry into the Easter bombings.