"The Gulf states and Egypt are now bonded together in the belief of the Muslim Brotherhood as their common enemy," said Christopher Davidson, an expert in Gulf affairs at Britain's Durham University. "This is a powerful alliance."
The Gulf's rulers have long considered the Brotherhood as a danger. In Saudi Arabia, for example, the Brotherhood's version of political Islam is seen as a challenge to the country's monarchy backed by the strict Wahhabi interpretation of Islam. The group is also seen as part of the wave of Arab Spring upheavals, which so far Gulf rulers have ridden out, though not without clampdowns on social media and other tools of budding political opposition.
Now, Gulf officials have become fearful of anything that could serve as potential footholds for the Brotherhood. In rhetoric at least, the group has begun to replace Iran as the most worrisome threat in the eye of many officials. The exception is Qatar, which has cultivated the Brotherhood regionwide and strongly backed Morsi.
In July, Dubai's police chief, Lt. Gen. Dahi Khalfan Tamim, warned of an "international plot" by the Brotherhood to undermine Gulf leaders and expropriate the region's huge riches. Last week, he posted a Twitter message directed at the Brotherhood and its backers: "You must know that everyone from the ocean to the Gulf hates you."
"My father is a victim of this kind of this paranoid thinking," said Hasan al-Jaidah, the son of the detained doctor. "My father's political views are of no threat to anyone. He is no radical or seeking to overthrow anyone. What are the charges? What are they claiming he did?"
Al-Jaidah's family claims he has no active role with the Brotherhood and says he worked as the assistant manager of medical services for state-run Qatar Petroleum.
The accusations against others have been severe: Seeking to topple the UAE's ruling families.
In early July, 69 people including a cousin of one of the UAE's ruling sheiks received prison sentences of up to 15 years after being convicted of links to an Islamist group, Al-Islah, suspected of ideological ties to the Brotherhood. Some of those jailed launched a hunger strike more than a month ago, alleging abuses behind bars.
At least three people have been taken into custody for social media posts about the trial, said the press freedom group Reporters Without Borders. One of them, blogger Waleed al-Shehhi, has been held since May.
The UAE also says it's planning another high-profile trial against 30 Egyptian and Emirati suspects for alleged coup plots linked to the Brotherhood.
This is in addition to ongoing arrests such as al-Jaidah's.
The doctor has been allowed to see family members once a month since he was detained Feb. 26, said his son Hasan. His father is brought blindfolded to the meeting spot in Abu Dhabi, not knowing where he is being held.
"We have no privacy at all with him," said Hasan. "Security officials are sitting right there at the table with us."
Last month, a Dubai-based Egyptian journalist, Anas Fouda, claimed he was held in a secret UAE prison for a month on suspicion of Brotherhood ties. Fouda was deported and now lives in Qatar.
"I went through a kind of hell for no reason," said Fouda, who denies being an active Brotherhood supporter. "I am not the only one."
In Cairo, Sara Sonbol says UAE authorities in December blocked the airport departure of her father, Mohammad Ali Sonbol, a Muslim Brotherhood supporter working in Dubai for decades. Later, they arrested him.
"A force of maybe 10 people came and they took him ... We called the police (and they said) that they have no idea and it could be a national security thing," she said.
Pro-government newspapers in Saudi Arabia often feature statements by King Abdullah equating protests by Brotherhood supporters in Egypt against that country's new leadership as "sedition." Last month, a Kuwaiti cleric was dismissed from a Saudi-owned TV channel for Brotherhood links.
In Kuwait, where Brotherhood-affiliated groups have some political space, a lawmaker in January urged officials to be on the alert for Brotherhood "sleeper cells" opposing the U.S.-backed emir.
"What's happening in the UAE is very sad indeed," said former Kuwaiti lawmaker Mohammad al-Dallal, whose Islamic Constitution Movement has ideological links to the Brotherhood, though its ties to the group are strained after some Brotherhood leaders were seen as supporting Iraq in its 1990 invasion of Kuwait. "We hope that they would put an end to this soon."
UAE officials decline to comment directly about the Muslim Brotherhood arrests, but have used editorials and state-backed groups to make their case.
Salem Humaid, director of the Al-Mezmaah Studies and Research Center which Humaid said was created to "give voice" to official positions described the Brotherhood as "terrorists" seeking to bring down the UAE's cosmopolitan society.
He boldly predicted: "This is the end of their story ... No more Muslim Brotherhood."
Davidson believes the Brotherhood also plays a convenient role as "bogey man" as Gulf states increasingly tighten political controls since the Arab Spring.
"They need to portray them as an enemy of the state," said Davidson. "This justifies the harsh measures adopted to protect the state."
