The Senator was arrested after he returned to the scene of an earlier theft.
The lawmaker, who was recently suspended, sneaked in through one of the glass barricades within the National Assembly complex and had the mace seized. The hoodlums that accompanied the Senator escaped from the chamber with the mace and fled in a black SUV. The mace is the symbol of authority in the Senate and no plenary sessions can legitimately take place in its absence from the chamber.
The Senate had recommenced Wednesday's session after a spare mace was brought in, and lawmakers had authorised the Nigeria Police Force and the Department of State Services (DSS) to retrieve the mace.
Police officers arrested him around 1:50pm when he returned to the upper legislative chamber while the recommenced session was going on. He was taken away in a black sport utility vehicle (SUV).
The lawmaker refused to respond to questions about the incident as he was led away.
On April 12, 2018, Senator Omo-Agege was suspended for 90 legislative days for his conduct in objecting to the electoral amendment bill which is seeking to reorganise the order of elections in the country.
Omo-Agege, alongside nine other Senators, had staged a walkout after the Senate passed the bill. Following criticism that trailed his allegations that lawmakers were plotting against the president, he apologised to his colleagues.
The lawmaker had also been in the Senate's firing line for his involvement with a group called "Parliamentary support group in Senate for President Muhammadu Buhari".
When his case was referred to the Senate Committee on Ethics and Privileges, the lawmaker approached the Abuja division of the Federal High Court to challenge the investigation.
The committee went ahead to recommend a 181-day suspension which was later reduced to 90 by the Senate President, Bukola Saraki.
Saraki also recommended a termination of the parliamentary support group within the Senate and a withdrawal of the case instituted against the red chamber in court.
The ruling All Progressives Congress (APC) has released a statement in reaction to the incident, condemning it as "an attack on our democracy".
The statement read, "The attention of the All Progressives Congress (APC) has been drawn to the invasion of the Nigerian Senate by suspected thugs who disrupted Wednesday’s plenary and made away with the mace.
"The APC hereby condemns this action and views it as an attack on our democracy and a desecration of the hallowed institution of the National Assembly.
We therefore call on security agencies to take all necessary actions to recover the stolen mace and ensure that the perpetrators and their sponsors are brought to justice."
Senator Omo-Agege, who is the prime suspect in the theft case, is a member of the APC.