"Should we go to this operations room, or this one?" the assistant asked cryptically.
Aqidi, who heads the Aleppo Military Council, was planning a dinner with a group of Syrian rebels on the front lines that night. But even here, in the heart of opposition territory, he and his aides were wary of discussing their movements aloud.
"There are lots of spies," he said. "They hurt us; they inform the regime of our movements and our battles. When I go out, the people in my own party don't even know where we're going."
For more than four decades, Syria's ruling family -- President Bashar Assad and his late father, Hafez -- has depended on informants -- or the fear of them -- to help keep the population in line.
"It was a regime of informants," Aqidi said.
The fear remains strong in the midst of a civil war that has destroyed entire towns and fragmented the population, the legacy of an era when the Assads held a tight grip on Syria and loyalty and information were for sale.
The government and opposition groups alike rely on spies to wage urban warfare and attack military targets. High-level government officers who want to defect, for example, may be asked to remain in place to feed information to the rebels. Likewise, rebels say they've suffered numerous setbacks because of spies and informants among their ranks.
There's a joke among some in the opposition: Who is the leader of the Free Syrian Army? Bashar Assad. Because everyone is an informant.
The Free Syrian Army's general staff has created its own intelligence branch to weed out spies and to recruit them within the government. All of the vehicles in Aqidi's convoys are riddled with bullet holes from attacks he believes were made possible by spies in the rebel ranks. Last year, his son was wounded in one such attack.
Aqidi has changed his cellphone number so many times -- believing it was tracked -- that he struggles to remember it.
The opposition's fear of informants now extends to journalists and humanitarian workers, who increasingly risk being kidnapped in rebel areas where their presence was once welcomed. In August, a militant website issued a recommendation that all journalists be kidnapped, interrogated and searched under suspicion of being spies.
Last month, clashes erupted between Free Syrian Army rebels and the al-Qaida-linked rebel faction known as the Islamic State of Iraq and Syria when the latter tried to detain a German doctor who had gone to a local hospital. The al-Qaida-linked group alleged that the doctor had been taking video of its headquarters in the town in order to spy.
In Bustan Qasir, an opposition-held neighborhood in the heart of Aleppo that abuts government territory, journalists and media activists are not allowed to take photographs or video before they are vetted by rebel commanders.
"I fear that there might be spies among them," said Sheik Aamir Abu Huthaifa, a commander in the district. "They might expose our positions."
Brig. Gen. Yahya Bittar, who heads the intelligence division of the Supreme Military Council, the nominal head of the Free Syrian Army, said he has operatives throughout Syria who monitor FSA rebel groups for possible informants.
Bittar, a former fighter pilot, said his operatives have had intelligence training and that his division has officers who worked for various government branches, including national security and military security.
Suspected informants are monitored and eventually brought to the intelligence headquarters in Bab Hawa, by the Turkish border, or handed over to local Islamic courts for interrogation. Bittar denied that detainees are beaten and tortured, for which the government prisons are notorious.
"It's the threat of beatings that gets him to confess," he said.
Those found guilty of spying can face prison or death.
Evidence deemed incriminating is often circumstantial. Rebels point to direct shelling on their bases and operation rooms as indicative of spies within their midst, even though few targets in opposition areas are spared from attacks.
Suspicion can be aroused when a rebel takes a phone call in private, especially if it's followed by shelling in the area, or by a fighter who never takes part in battles, commanders said.
In July, a newly formed brigade under the command of the Supreme Military Council prepared to launch an offensive on Khan Assal, a strategic government-held suburb of Aleppo.
At the last minute, the attack was postponed, with no new date announced.
"To keep the spies from knowing our plans," explained Lt. Col. Maan "Abu Bakir" Hijazi, commander of the 19th Brigade. "Ninety percent of our battles are a surprise."
Suddenly at sundown on a Friday, as the fighters were preparing to break their Ramadan fast, the launch of the attack was ordered. The battle lasted for three days until the rebels seized control of the suburb.
"The informant in our ranks hurts us more than we benefit from the informants we have in the regime," Bittar said. "When someone gives us information, they are afraid because the regime monitors all lines of communication, but we can't monitor all lines so (rebels among us) can more easily communicate with the regime."
The rebels rely on checkpoints to weed out those who might be spying.
At the crossing that connects opposition -- and government-controlled Aleppo, rebels stopped a family for questioning. The man, woman and their young son were forced off their motorcycle and rebels searched the storage compartment, looking closely at documents, handwritten letters and photos.
"Reports," said Abu Jameel, a rebel with a militia based in Bustan Qasir, when asked what he was looking for. "People write reports on what is happening here. Sometimes men come dressed as women. They write about the FSA and the number of soldiers we have."
The woman stood by as her son looked up at her, whining. The man maintained a strained smile. Other young rebels gathered to look over the papers; everyone wanted to take part in the inspection.
"Hold on, I saw the word 'Assad,'" said a skinny teen who was craning his neck over the shoulders of the other rebels.
"That's where I was taking exams," the man said quickly.
The teenager didn't seem convinced. But soon Abu Jameel handed the now-disheveled stack of papers back to the man and the family was allowed to pass.
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