The Office of the National Security Adviser (ONSA) has asked former Kaduna State governor, Nasir El-Rufai, to forward any evidence in his possession on the alleged procurement of a toxic chemical to the Department of State Services for investigation.
This followed a petition addressed to the National Security Adviser, Nuhu Ribadu, in which El-Rufai alleged that about 10 kilograms of thallium sulphate had been sourced from a supplier in Poland.
Thallium sulphate is a highly toxic, colourless and odourless substance capable of causing death in small quantities.
In a response dated February 13, 2026, and signed by a brigadier-general, O.M. Adesuyi, on behalf of the Office of the National Security Adviser, the NSA’s office denied the claim and said the matter had been handed over to the DSS.
“I have the honour to… acknowledge receipt of Your Excellency’s correspondence received on 11 February 2026 requesting clarification regarding the alleged procurement of approximately 10 kilograms of Thallium Sulphate by the Office of the National Security Adviser (ONSA),” the letter said.
The response added that the allegation had also suggested that information on the purported transaction was available to leaders of the political opposition.
In its reply, ONSA stated that it had no involvement in the alleged transaction.
“I am directed to respectfully convey that ONSA has neither procured nor initiated any process for the purchase of such material, and has no intention of doing so,” the letter read.
However, the NSA’s office confirmed that the allegation had been formally referred to the DSS for a detailed probe.
“I am further directed to state that the allegation has been formally referred to the Department of State Services for a comprehensive investigation,” the letter stated.
It added that El-Rufai and any other persons with relevant information would be contacted by the security service.
“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.”
Sources said an earlier attempt to deliver the letter to El-Rufai’s Abuja residence was unsuccessful on Friday, as security personnel on duty reportedly declined to accept the document. The letter was eventually delivered on Sunday and received on his behalf.
The development comes amid fresh claims by the former governor that he had access to an intercepted telephone conversation involving Ribadu.
Speaking on Arise TV, El-Rufai had alleged that the NSA’s phone had been tapped and that he listened to a call in which Ribadu was said to have directed security operatives to arrest him.
He said during the programme that “someone tapped” the NSA’s phone and that he heard instructions allegedly given to security agencies to take him into custody.