Mohamed Hashim Mathaniya is the sister of Mohamed Zahran Hashim, the man Sri Lankan authorities believe was one of the leaders of the attacks.
Cardinal Malcolm Ranjith said the Church was closely monitoring government investigations into the April 21 suicide attacks and wanted to be sure of the security situation before returning to daily services.
The following day, April 22, an explosion went off in a van near a church in Colombo, when bomb squad officials were trying to defuse three bombs found in it. Sri Lankan police also found 87 bomb detonators at the main bus station in Colombo.
"We can not kill someone in the name of God ..."
Nancy VanHorn, the spokesperson at the US Embassy in Colombo reportedly said, "As the (US) Ambassador (Alaina Teplitz) has previously stated and as reflected in our travel advisory, the terrorist threat is ongoing".
Authorities suspect two members from ISIS groups - National Thawheedh Jamaath (NTJ) and Jammiyathul Millathu Ibrahim - of carrying out the attacks.
Sri Lankan officials have warned that suspects linked to the attacks are still at large.
The National Investigation Agency said in a statement late Monday that Riyas A., also known as Riyas Aboobacker, was arrested.
"This is why I concentrated on ensuring people's security rather than spending time debating with others on the Easter Sunday attacks", he said, adding that many arrests had been made and arms were being recovered due to the ability of security forces and the intelligence units.
The statement did not provide any details about Aboobacker's alleged plot in Kerala.
"As such, all activities of those organizations as well as their property will be seized by the government", his office said. It asked the public to "act in a responsible manner" on social media.