The State Security Service on Tuesday warned the public to desist from engaging its disgraced former director-general, Lawal Daura, on its behalf.
The secret police said it has been inundated with insinuations that Mr Daura still wields influence in its internal affairs, months after he was fired from office.
Mr Daura, appointed in 2015 by President Muhammadu Buhari, was fired on August 7, 2018, by then-Acting President Yemi Osinbajo, after ordering a controversial siege to the National Assembly in an alleged bid to force a leadership change.
Mr Daura was initially placed in a police detention, but was released a few days later amidst undisclosed circumstances.
There have been claims that he still occupies official quarters of the SSS, while remaining involved in the affairs of the agency.
But in a Tuesday morning statement, the SSS said it was aware of the "false" speculation, and warned people to shun any involvement with Mr Daura on its behalf.
"While the Service debunks this false belief, it warns that any person or group that further engages him or his representatives/associates does so at their own peril," SSS spokesperson Peter Afunanya said in a statement.
"The Service will not tolerate acts of impersonation designed to undermine it and will decisively deal with person(s), no matter how highly placed, that may engage in such behaviour.
"The public should, therefore, note this and avoid circumstances under which unsuspecting persons may be," Mr Afunanya said.
The SSS did not offer specifics on whether or not it was in possession of credible complaints about questionable deals involving Mr Daura and unsuspecting persons prior to its statement today.