Former Brazilian President Luiz Inácio Lula da Silva is back in prison after being let out to attend his grandson Arthur’s funeral.

The seven-year-old died of meningitis on Friday. Lula, as he is known, was allowed to go to the burial in São Paulo on Saturday, where supporters gathered to greet him.

Lula is serving 12 years in prison on corruption charges.

At the funeral, the former president insisted on his innocence.

Lula’s website said he announced at the funeral that when he met Arthur in heaven, he would prove his innocence after all the bullying that the boy had suffered in school due to his grandfather being in prison.

Lula, who claims his conviction was politically motivated, would also prove that the prosecutor and judge who jailed him lied, the note added.

An iconic figure for the left in Latin America, the former trade unionist led Brazil between 2003 and 2010.

But he was convicted for work done on a beachfront property. In February a court doubled Lula’s sentence after he was found guilty of benefiting from renovation work from a company implicated in a corruption scandal.

His lawyers said he would appeal against the new conviction.