According to a report in Daily Mirror, Pakistan authorities had alerted the Sri Lankan High Commissioner in Islamabad. The alert was mentioned in the report of the Presidential Inquiry Commission that had been constituted to investigate the deadly 2019 serial bombings.Serial bombings on Easter Sunday in 2019 had killed 259 people, mostly minorities Christians, in Sri Lanka.

“The Pakistani authorities had also handed over information about the suspect along with his pictures. The dossier of information about the suspect contains a handbook on armed training, and details regarding improvised explosive devises, vehicle-borne improvised explosive devises,” Daily Mirror reported.

However, the same inquiry report said the person was not connected with the Easter bombings.

Interestingly, just around two weeks ago, Indian intelligence agencies had provided intel inputs on impending terrorist attacks. However, the Sri Lankan security establishment failed to act to foil the attack.   
Soon after the attack, as it became clear that there were prior intel inputs on the attack, the Sri Lankan political leadership faced heavy public criticism over their inability to stop it.