Charles Okah, a former militant leader, will spend the rest of his life behind bars after being found guilty of plotting the 2010 Independence Day bombing that left at least 12 people dead in Abuja, a federal judge ruled on Wednesday.

Gabriel Kolawole of the Abuja Division of the Federal High Court also sentenced Mr. Okah’s co-conspirator, Obi Nwabueze, to life following a trial that lasted nearly seven and a half years over the Independence Day bombing and another bomb attacks that occurred in Warri, Delta State, on March 15, 2010.

One person died in the Warri attack after three explosives were separately detonated at the venue of a peace dialogue aimed at getting more militants who were terrorising the Niger-Delta at the time to embrace the federal government’s amnesty programme.

“The defendants are guilty as charged and hereby convicted,“ Mr. Kolawole said, noting that the four-and-a-half hour judgment was the longest he had ever written.

More than 36 persons were severely injured when crowds gathered to celebrate Nigeria’s 50th Independence Anniversary which had then-President Goodluck Jonathan in attendance at Eagle Square.

As early as October 2, federal authorities began making arrests in connections with the bombing, which Mr. Jonathan said was targeted at assassinating him.

Four persons were initially charged for their roles in the bombings by the Nigerian government when the trial began on December 7, 2010, but only Messrs. Okah and Nwabueze had their trial drag for this long.

Edmund Ebiware received a life sentence after being found guilty of three counts of accessory to murder on January 25, 2013. The last man, Tiemkemfa Francis-Osvwo, who played active roles in Niger-Delta militancy, died during trial in Kuje Prisons between March 3-4, 2012.

Mr. Ebiware and his wife, Ify, maintained that he is innocent of the terrorism charges and said in 2015 that they were planning to appeal his conviction.

Charles Okah’s brother, Henry, was arrested in South Africa, where he has lived since 2003, also in October 2010 and was sentenced to 24 years’ imprisonment in March 2013 for his role in the bombing. On February 23, 2018, the Constitutional Court in South Africa affirmed Mr. Okah’s sentence, ending a series of appeals that dragged for four years.

They all belonged to the defunct Movement for the Emancipation of the Niger-Delta (MEND), a foremost militant group that claimed credits for a series of attacks on oil installations and public facilities across the oil-rich region between 2005 and 2014.

The group, which said it was fighting for the social and economic advancement of the ethnic groups in the region, was also linked to several kidnappings of oil workers, especially the expatriates working for major international oil firms.

Moments before Mr. Kolawole sentenced Messrs. Okah and Nwabueze yesterday, their lawyers pleaded for mercy, citing their remorse for the offences and the plight of their respective family members.

“It wont benefit the state if the convict is in prison for life as he poses no further danger to the state,” said Emeka Okoroafor, a counsel to Mr. Okah, adding that his client has children and elderly mother.

Mr. Nwabueze’s lawyer, Oghenevo Otemo, urged the court to be lenient towards his client because he had no criminal record.

“We also adopt submission made by the first defense counsel, the second defendant has never been arrested, charged or convicted in court,” Mr. Otemo said. “He has shown remorse, he will not pose any danger to society if a lesser sentence is accorded.”

But the prosecutor, Alex Izinyon, a senior lawyer, kicked against any clemency for the defendants, arguing that they caused untold hardship on families of the victims and the nation as a whole.

Mr. Izinyon argued that the convict’s offences contravened Section 14 (1) and (2) of the Economic and Financial Crimes Commission (Establishment) Act and said they both deserved life behind bars for terrorism and financing of terrorism.

Mr. Kolawole said oral and documentary evidence provided by the prosecution satisfied the demand life imprisonment for Mr. Okah and his accomplice.

He said they provided funds to purchase the vehicles that were used in the bombings in Warri and later in Abuja in 2010.

The accused achieved their terrorism purpose and must face the consequences of their action, Mr. Kolawole said, before handing down life sentences for the duo.

Liborous Oshoma, a civil rights attorney, hailed the ruling as an act of judicial prudence.

“It is good to see the law being activated against those who took laws into their own hands,” Mr. Oshoma said. “The judiciary has sent another strong message to those who have criminal intentions.”

Mr. Oshoma said Nigerians should now look forward to the day when those behind Boko Haram would be unmasked, arrested and be made to stand trial for their heinous crimes against Nigerian citizens.

Mr. Okah’s mother and two sons were at the court during the sentence. It was not immediately clear whether relatives of the later victims or those who survived the attacks were present.

The defense lawyers did not immediately clarify whether their clients planned to appeal the ruling.