According to Sri Lankan government officials, all nine suicide bombers involved in the attacks were Sri Lankan citize…

According to Sri Lankan government officials, all nine suicide bombers involved in the attacks were Sri Lankan citizens associated with National Thowheeth Jama'ath (NTJ), a local Islamist militant group founded by Zahran Hashim, and known for attacks against Buddhists and Sufis or the Jamathei Millathu Ibrahim (JMI), a smaller group of youth. On 23 April, State Minister of Defence Ruwan Wijewardene theorized that the attack was in retaliation for the Christchurch mosque shootings which occurred

Sources

• Wikipedia