The Office of the National Security Adviser has challenged former Kaduna State Governor, Nasir El-Rufai, to submit any evidence in his possession regarding the alleged procurement of thallium sulphate to the Department of State Services for investigation.
The ONSA, headed by Nuhu Ribadu, was reacting to claims by El-Rufai that the office procured about 10 kilograms of thallium sulphate, a toxic chemical compound, allegedly sourced from a supplier in Poland.
Thallium sulphate is known to be a highly poisonous, colourless and odourless substance capable of causing death even in small quantities.
El-Rufai had earlier accused the ONSA of being behind the purported transaction and demanded an urgent explanation over the matter.
In a formal response, however, the security office firmly denied the allegation and maintained that it neither procured nor initiated any process for the purchase of the substance. It also stated that it had no intention of doing so.
The ONSA disclosed that the allegation had been referred to the DSS for a thorough probe and urged El-Rufai and any other individuals with relevant information to cooperate with investigators by providing credible evidence.
According to a report by TheCable, an initial attempt to deliver the response letter to El-Rufai’s Abuja residence was unsuccessful, as security personnel on duty reportedly declined to receive it, citing the absence of the head of security.
The letter was eventually delivered on Sunday, with the head of security signing for it on behalf of the former governor.
The correspondence, dated February 13, 2026, was signed by Brigadier-General O.M. Adesuyi on behalf of the National Security Adviser.
In the letter, the ONSA acknowledged receipt of El-Rufai’s earlier communication dated February 11, 2026, seeking clarification on the alleged procurement.
It further stated that claims regarding the purported purchase were said to be in the possession of political opposition figures, adding that the DSS would invite all relevant parties to provide information to ensure a comprehensive and diligent investigation into the matter.