The CIA and its friends know how to create 'suicide bombers'
"The CIA experimented extensively with brainwashing during the 1950s and 1960s, honing techniques that could force someone to kill, then have no recollection afterward.
"Some 44 universities, 12 hospitals and three prisons helped out with the experiments."
https://nypost.com/2016/07/23/the-dark-cia-experiments-that-inspired-jason-bourne-movies/
Ten days before the bombings on Easter Sunday, a top Sri Lankan police official warned the security services that the National Thowheeth Jama’ath (NTJ) was planning attacks against churches.
"No action was taken against the group."
https://www.nytimes.com/2019/04/22/world/asia/ntj-warning-sri-lanka-government.html
The Sri Lankan military has received specialized training assistance from Israel and the United States and India
In the period December 2018 - January 2019, Israelis from United Hatzalah were in the Sri Lankan capital Colombo to train local teams for mass-casualty incidents, including mega-terror attacks.
"The program, a joint effort of the American Jewish Committee and United Hatzalah, began in December 2018 and continued into January, with training programs in Sri Lanka.
"The team from Israel provided training to members of the military, police force, search and rescue units and the fire department in Sri Lanka."
http://www.israelnationalnews.com/News/News.aspx/262154