"I decided to appear before the committee as a mark of respect for the Senate," the IGP said.
Senator Isa Misau had accused the IGP of pocketing the sum of N10 billion illegal cash monthly.
Idris who was accompanied by senior police officers told the senators that he would not answer any question as the matter was in court.
Quoting Order 41(7) and 53(5) of the Senate standing rule, the IGP maintained that the Senate cannot interfere or make pronouncement on a matter that was already in court.
His words: "I’m represented by a Senior Advocate of Nigeria, Alex Izyon. He is going to refer to as my true response on allegations made by Senator Isa Misau against me.
"I will not make any other comment or answer any question in respect to the allegation and various civil and criminal cases pending in the law court. More especially, when the Senator has already been arraigned in court in respect of these matters. I decided to appear before this Senate committee on the allegations out of the high respect I have for the Senate and my penchant for the rule of law.
"Futhermore, it is expected that the Senate and the committee will refrain from making reference to the issue as it would be against order 41 (7) and 53 (5) of the Senate standing order 2015 as amended," he added.
Counsel to the IGP, Alex Izyon (SAN) said responding to questions would amount to subjudice as the matter was already before a court of law.
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Izyon urged members of the committee to study the documents earlier submitted to them by the IGP.
In his National Assembly, Senator Francis Alimikhena noted that the matter was already before the committee before the IGP approached the court.
Alimikhena reiterated that the court could not prevent the committee from carrying out its constitutional duty of investigation.
In his remarks, Senator Ita Enang urged the lawmaker to apply the multi-door approach to resolving the matter.
The committee adjourned the matter.