The International Criminal Court has convicted a former commander in the Ugandan rebel group the Lord’s Resistance Army (LRA) of dozens of war crimes and crimes against humanity ranging from multiple murders to forced marriages.

Dominic Ongwen was abducted by the shadowy militia as a nine-year-old boy and transformed into a child soldier and later promoted to a senior leadership rank.

He will be sentenced at a later date by the court in The Hague, in the Netherlands and faces a maximum punishment of life imprisonment.

The judgment outlined the horrors of the LRA’s attacks on camps for displaced civilians in northern Uganda in the early 2000s, and of Ongwen’s abuse of women forced to be his “wives”.

Presiding Judge Bertram Schmitt said that Ongwen’s history as an abducted child turned fighter could be considered at the sentencing stage of the trial.

But he made clear: “This case is about crimes committed by Dominic Ongwen as a fully responsible adult as a commander of the LRA in his mid-to-late 20s.”

Defence lawyers had argued that Ongwen was a “victim and not a victim and perpetrator at the same time”.

Reading a summary of the written judgment, Judge Schmitt outlined the brutal rein of terror unleashed by the LRA, which was founded and led by one of the world’s most-wanted war crime suspects, Joseph Kony.

Female civilians captured by the group were turned into sex slaves and wives for fighters while children were transformed into child soldiers. Men, women and children were brutally murdered.

“Civilians were shot, burned and beaten to death,” Judge Schmitt said as he detailed the horrors of an attack on the Lukodi camp for internally displaced persons in May 2004 carried out by fighters commanded by Ongwen.

Kony promoted Ongwen to the rank of colonel after the attack.

Judge Schmitt rejected claims by the defence that Ongwen was suffering from mental illness and that he was acting under duress when committing the crimes.

Ongwen showed no emotion as Judge Schmitt read out the verdicts. Usually, defendants are ordered to stand as the presiding judge reads out the verdicts. In Ongwen’s case, there were so many that he was allowed to remain seated.