The Office of the National Security Adviser (ONSA) on Sunday denied acquiring thallium sulphate, a highly toxic, colourless, and odourless substance that can be fatal in small amounts.
The denial came in response to a letter dated January 30, 2026, from former Kaduna State governor Nasir El-Rufai to National Security Adviser Nuhu Ribadu.
In his letter, El-Rufai claimed that information obtained by political opposition leaders indicated that the NSA had purchased about 10 kilograms of thallium sulphate from a supplier in Poland.
In a reply signed by Brigadier General OM Adesuyi on behalf of Ribadu, ONSA confirmed receipt of El-Rufai’s letter and categorically denied the allegation. “ONSA has neither procured nor initiated any process for the purchase of such material, and has no intention of doing so,” the statement signed by Mr Adesuyi, stated in the letter, first published by TheCable.
The letter added that the matter had been referred to the State Security Service (SSS) for a comprehensive investigation, and that Mr El-Rufai and other parties in possession of relevant information would be invited by the service to provide evidence. “Your Excellency and other parties involved, who may possess relevant information relating to this claim, will be duly invited by the Service to provide any evidence that may assist in an in-depth investigation, establishing the facts and ensuring due diligence,” the letter read.