The court, which however advised Maina to honour the invitation sent to him by the Senate, also restrained the Senate perpetually from ordering his arrest based on the warrant already vacated by the court.
Presiding judge, Justice Adamu Bello, who vacated the arrest warrant issued against Maina, said even though the Senate had the power to summon anyone, that power was not absolute.
According to the court, the power of the Senate to summon individuals to appear before it is also subject to the fundamental human rights of the individuals as provided for in the constitution.
Justice Bello therefore held that the Senate had also ignored the procedure governing its power in the performance of its oversight functions.
He said the Senate should have first published in its journal or the official gazette of the federation, the notice inviting Maina, maintaining, however, that his judgement should not be misinterpreted to mean that the Senate does not have the powers to investigate or summon any person to give evidence regarding any subject matter under investigation.
"From the reliefs sought by the applicant, the application is challenging the powers of the Senate to issue a warrant of arrest, a careful perusal of Section 35(1) shows clearly that the right of liberty guaranteed the applicant by the Constitution is absolute.
"Going by this, the applicant is entitled to a fair hearing. The issue now is to determine whether the applicant's case falls on the exceptional clauses.
"Section 88(2) of the 1999 Constitution gives the National Assembly the power to invite or summon an individual for questioning in order to expose corruption, inefficiency among others.
"However the power of the Senate is subjected to the provision of Section 88 of the 1999 Constitution which highlighted the conditions to follow before an individual will be summoned.
"This power of the Senate should be free from abuse and the term of reference should be clear.
"Any invitation by the Senate outside the purpose highlighted in Section 88(2) is illegal and unconstitutional.
"The Senate ought not to have invited the applicant in the first place, a proper investigative committee must have been constituted in accordance with constitution.
"The power to call for investigation by the Senate under Section 88(2) is predicated on a published resolution.
"The respondents have failed to produce or annex vital documents to their counter affidavit, they only exhibited the warrant of arrest signed by the Senate President.
"The implication of not producing such vital documents means there is no evidence before me to show that investigation is going on the subject matter.
"The warrant of arrest was not validly issued, it is therefore set aside.
"Relief one is hereby granted, the respondents are perpetually restrained from arresting the applicant on account of the warrant arrest being set aside.
"I will only advise the applicant to submit himself to the Senate," Justice Bello ruled in his judgement.
Citing the Supreme Court judgment of Tony Momoh V Senate,thhe judge held that the conditions precedent for inviting Maina are by stating why he (Maina) was being invited.
It would be recalled that Maina had approached the court for an order setting aside the warrant of arrest issued at the instance of the Senate by th Inspector General of Police, Muhammed Abubakar against him on Februar 2, following a resolution by the Senate.
He also prayed the court to quash the purported report of the Senate Committee’s resolutions that led to the issuance of the bench warrant, as the action violated his fundamental rights as guaranteed under Section 35(1) of the 1999 Constitution.
Maina is further praying the court to restrain the Senate from interfering with his official duties and from inviting him having completed and submitted their report without giving him fair hearing.
He asked for N100 billion as exemplary damages and N500, 000 as general damages.
The respondents in the suit are, the Senate President, the Senate,Clerk of the Senate, the Senate Committee on Establishment and Public Service and its chairman, Senator Aloysius Etok; and the Senate Committee on State and Local Government Administration and its chairman, Senator Kabiru Gaya.
Speaking after the judgment, Maina's lawyer, Mahmoud, SAN said he was excited because the court had upheld the rule of law.
He said that the Nigerian judiciary has once again shown that it is the custodian of the law.
He said that Maina was not challenging the powers of the Senate and that he also was not being disrespectful to the Senate but he went to court to show that the Senate must follow due process in exercising its powers.
He said Maina did not flee the country but went underground because of the threat to his life.
"I can make his international passport available to prove that he did not run away. But for the fear for his life and safety for his family he chose to go under ground," Mahmoud said.