DUBAI—A suspected member of an Iranian militant group based in California has been arrested by the Iranian government while allegedly staying at a hotel in Dubai, according to his family.

The family of 65-year-old Jamshid Sharmahd has been tracking his movements using the location data on his mobile phone and have informed authorities that he was potentially taken to Oman, then Iran.

It is unclear how they detained him when he was not in the country, as members of his family are questioning the legality of their actions.

“It is a violation of human rights. You can’t just pick someone up in a third country and drag them into your country,” his son Shayan Sharmahd told reporters.

Sharmahd’s family insists that reports of him being part of a militant group are inaccurate, stating that he was only a spokesperson. The Mosque attack in question occurred in 2008, killing 14 people, and wounding 200 more. The government has yet to announce what he has been charged with.

After being captured, the Iranian government brought Sharmahd onto their state-run television, where he confessed to being guilty for bombing the Mosque. His family believes he was forced to admit his role in the attack to spare his life.

The Intelligence Ministry in Iran has yet to give any details on Sharmahd’s detainment. According to a hotel operator in Dubai, he checked out on July 29, later going to the city of Al Ain, then crossing into Oman, where he stayed overnight near an Islamic school.

On July 30, the tracking signal for Sharmahd’s mobile phone ceased. His location is currently unknown. He has a dual German-Iranian citizenship, which gave his family  hope  they could receive help from the German embassy, asking for consular access, and getting a better understanding of his arrest. Iran refused this motion, as they do not allow consular access for dual nationals.

Sharmahd’s family states that he suffers from Parkinson’s, along with diabetes and heart problems, all of which require medicine to be kept under control.