US authorities seized wealthy activist James “Fergie” Chambers’s cellphone after Spanish police arrested him in July, his lawyer says, despite a court order that the device stay in Madrid while an extradition request was handled. Chambers is imprisoned in Madrid and is fighting a US bid to extradite him. His legal team says the phone was taken from Spain’s national court custody and handed to the FBI after they raised the issue with the court on Tuesday, according to attorney Aitor Martínez. Martínez said the defence received written guarantees that the phone would remain under the court’s custody while the extradition request was resolved, in line with Spanish law and the extradition treaty between the countries. Instead, he said a judge “secretly turned over” Chambers’s phone to the United States, meaning it left the Spanish courts’ control while the extradition fight continues. The defence filed a petition with an appeals court seeking the immediate return of the cellphone and a detailed account of its chain of custody, including who authorized the transfer, when it happened, and whether US agents accessed the phone’s contents. Martínez said the office of Spain’s minister of justice, Félix Bolaños, may need to be involved. Chambers, who applied for asylum while in prison, argues the extradition is politically motivated. His asylum application is ongoing, and his legal team says the process must block extradition until it is completed under Spanish law. The US extradition request includes allegations tied to alleged Hamas support linked to donations Chambers made to back projects supporting Palestinians, including in Gaza. It also includes charges connected to a protest against Elbit Systems. Chambers is currently held after a judge denied provisional release earlier this month, citing his wealth and alleged flight risk. Aitor Martínez said a 1970 treaty limits release of possessions of a person sought for extradition to the requesting country only after extradition is granted. Meanwhile, Chambers’s partner and attorney, actor and activist Stella Schnabel, told the Guardian she retrieved his personal effects last month at the prison, including keys and identification, though she said it was unclear whether the phone had already been surrendered by then. Chambers remains in custody in Madrid as Spain’s courts handle the extradition case and his asylum bid continues from prison.