Nigeria, Feb. 16 -- The Office of the National Security Adviser (ONSA) on Sunday denied procuring thallium sulphate, a highly toxic, colourless and odourless compound capable of killing humans in small doses.

The denial was issued in response to a letter from Nasir El-Rufai, former governor of Kaduna State, to the National Security Adviser, Nuhu Ribadu, dated 30 January 2026.

In the letter, Mr El-Rufai said information available to the political opposition leadership suggested that the NSA had procured approximately 10 kilogrammes of thallium sulphate from a supplier in Poland.

In a reply by OM Adesuyi, a brigadier general, signing on behalf of Mr Ribadu, the ONSA acknowledged receipt of Mr El-Rufai's correspondence and denied the alle...