Ten days before devastating bombings on Easter Sunday, a top Sri Lankan police official warned the security services in an advisory that a little-known radical Islamist group was planning suicide attacks against churches. Top government officials say the warning never reached them, and no action was taken against the group.

On Monday, the government blamed the group, National Thowheeth Jama’ath, for the attacks, saying it received help from unspecified international terrorist organizations.

Here is a translation of the cover letter and summary of the advisory. In several cases, The Times has redacted an address or phone number from the translation.