Istanbul (CNN) -- For years, Abdullah al-Omar rubbed shoulders with some of the most powerful people in Syria.
In case there is any doubt, he is quick to show photos in his phone as proof.
Scores of photographs show the corpulent Syrian beaming and shaking hands with government ministers, foreign dignitaries, and even the Syrian president.
"He knew me by name," al-Omar said, pointing to a photo of himself standing with Bashar al-Assad. "One day we were sitting at a table and he fed me with his own hand and said to me, 'You love food since you are from Aleppo.' Then he said to his escort, 'Take special care of Abdullah al-Omar because he loves food and his stomach.'"
Al-Omar claims that for five years he worked in the press office of the presidential palace in Damascus, as part of a 15-person team under the direction of long-time government spokeswoman and presidential adviser Bouthaina Shabaan.
Until he defected and fled the Syrian capital last month, al-Omar said, the bulk of his work consisted of lying.
"Our job was to fabricate, make deceptions and cover up for Bashar al-Assad's crimes," he said.
It is impossible to independently confirm al-Omar's claims. The fact that he freely admits to a career as a government propagandist makes him a somewhat unreliable whistle-blower.
However, the editorial director of a pro-rebel media organization who asked not to be named for security reasons confirmed to CNN that he knows al-Omar worked for Syrian secret police.
"He is the biggest informant for the Al Jawiya," the Syrian journalist said, referring to Syria's much-feared air force intelligence agency. "He was a very strong informant who worked for the palace and worked for Bouthaina (Shabaan)."
During a four-hour interview in Istanbul, al-Omar described in detail some of the propaganda methods used by pro-government media.
During the government's artillery bombardment of the rebel-held neighborhood of Baba Amr in the city of Homs, loyalist women were brought in and disguised as locals for government television interviews, he said.
"The women would say that the massacres against men, women and children were perpetrated by armed gangs, when it was actually the Syrian regime, security forces and the Shabiha" -- the pro-government militia -- "who were behind these horrendous acts," al-Omar said.
These claims are backed by the accounts of residents of Homs, who spoke to CNN on condition of anonymity for fear of reprisal at the hands of Syrian security forces.
"I remember that day as if it was yesterday, when state TV showed Assad parading through Baba Amr, not a single resident was from the area," said a native of Homs, now exiled to neighboring Lebanon. "They brought them from neighboring towns from the countryside so they could pretend he was getting a hero's welcome, that he was greeted as a beloved leader, when in reality everyone in Homs knew he was behind the destruction of every house and the killing of every innocent civilian on Homs and every other city in Syria."
After protests erupted against the government in March 2011, al-Omar said, he was ordered to establish a pro-regime TV station in Aleppo.
A commercial on a Syrian website shows al-Omar holding a microphone in front of a banner advertising "Al Aleppia TV." Journalists in Aleppo said the station was a cheaply run operation that broadcast over the Internet.
One of Omar's assignments was to book pro-regime guests on his TV channel, as well as on larger international networks, to discredit defectors from the Syrian government.
"We would contact regime loyalists from Lebanon or Syria to appear as guests on Al Jazeera, Al Arabiya and other channels, to say these defectors are bad, corrupt, and not doing their jobs well."
Asked how his former colleagues would react to his own defection, al-Omar said, "they will follow standard procedure and say Abdullah al-Omar has nothing to do with the press office, and doesn't work in the presidential palace, and that they never heard of me and that I descended from heaven just to smear the image of the regime.
"But what will embarrass them," he continued, "is that I appear in a lot of pictures and videos, practically in all the press conferences for Bashar al-Assad and his official reception ceremonies."
There is ample photographic evidence to back this claim.
In more than a dozen photos, al-Omar is clearly seated at press conferences featuring al-Assad and a number of visiting heads of state, including Iranian President Mahmoud Ahmadinejad, former Russian President Dmitry Medvedev, and Venezuelan President Hugo Chavez.
Pictures also revealed al-Omar at the presidential palace and at what appear to be government receptions, posing alongside high-ranking officials like Shabaan, Syrian Foreign Minister Walid Moallem, and top members of the Syrian parliament and ruling Baath political party.
Al-Omar was also photographed alongside regime allies such as Palestinian Hamas leader Khaled Mashaal, the Iranian ambassadors to both Damascus and Beirut, and a bearded man al-Omar identified as the head of the politburo of Hezbollah.
"The Iranians met with Bashar al-Assad almost daily," Omar said. "Iranian security officials, high-ranking officers of the Iranian revolutionary guard, a lot of high-ranking officers."
In what may have been a breach of protocol, al-Omar also appeared in photos with former Lebanese President Emile Lahoud dressed in a shiny nylon track suit.
Omar offered tantalizing -- and impossible to independently confirm-- details about the inner workings of the presidential palace.
Throughout the bloody 19 months of the Syrian uprising, he said, the Syrian president grew increasingly irritable and anxious. Al-Omar described how al-Assad began nervously pacing the halls, and often stared out the windows of the hilltop palace down at the city of Damascus.
"Three or four months into the revolution, he seemed more preoccupied and more anxious, rarely did we see him smiling," al-Omar recalled.
"Sometimes we would see him do things with his head, hands or feet that are not appropriate for a president," he continued.
"One day I saw him kicking a table and he was cursing and swearing against the people of Homs, Rastan and Daraa, and he verbally abused the Sunnis and the Syrian people in general."
Al-Omar said al-Assad worked out of an office about 30 meters down the corridor from the room where the press department was stationed. He claimed the beleaguered president was obsessed with foreign media coverage of Syria.
"Bashar al-Assad has 16 TV screens in the meeting room, in his office, and also in the press office," the defector said. "Most news channels on the top row of the TV screens were Al Jazeera, Al Arabiya, BBC, CNN. ... He considered media people his first enemy. He hated them more than the revolution of the Free Syrian Army, especially the foreign reporters who enter Syria, because these were people who were showing the true picture and truth about what's happening in Syria. ...
"He would get very angry and swear, cursing the secret police and security forces saying, why can't they find out where these reporters are, capture them and 'bring them to me so that I can kill them.'"
There is no way to confirm al-Omar's claims, but several foreign reporters have lost their lives in Syria this year.
Veteran war correspondent Marie Colvin and photographer Remi Ochlik were killed by government artillery fire in Homs in February. They were among the first of a growing number of foreign journalists killed and wounded after entering Syria to report without government permission.
Meanwhile, the Syrian government has also held several foreign reporters in captivity for protracted periods without acknowledging their presence. With the help of Iranian mediation, Syrian authorities released Turkish journalists Adem Ozkose and Hamit Coskun in May, nearly two months after they disappeared in northern Syria.
The U.S. State Department recently announced that an American freelance reporter named Austin Tice is also believed to be in Syrian government hands. Tice disappeared in Syria last August. Meanwhile, a campaign has been organized in Turkey to lobby for the release of Cuneyt Unal, a Turkish cameraman who was captured in Syria and paraded on government television last August.
Amid efforts to crack down on voices of dissent as well as the growing armed insurgency, the presidential palace was not immune to danger, al-Omar said.
The biggest crisis took place in July, when a bomb killed four top security officials from the national crisis management bureau. Among the dead was presidential security adviser Hassan Turkmani, a stern-faced man with a mustache who was shown in several photographs standing alongside al-Omar.
Al-Omar claimed al-Assad narrowly missed the bombing by a few minutes. He also said Maher al-Assad, a top military commander and brother to the Syrian president, was gravely wounded in the bombing. He also claimed Maher al-Assad was transported to Russia for treatment.
When contacted by CNN, the Russian government did not immediately respond to al-Omar's allegation.
"Two days after he returned from medical treatment in Russia, Maher al-Assad came to the presidential palace," al-Omar said. "He had lost his left leg in the bombing and also the use of his left arm."
The president's brother has not been seen in public since the bombing. Shortly after the attack, diplomatic sources were saying Maher al-Assad had been badly wounded.
Al-Omar's motives for abandoning his position near the seat of power are not entirely clear.
It could be self-preservation. According to reports on several Syrian websites, al-Omar survived an attack in Aleppo by "armed terrorists" in 2011. Asked about the incident, the normally voluble al-Omar declined to comment.
Instead, the former propagandist said the turning point came last month, when he drove through his hometown of Atareb in the north of the country.
"I swear I cried when I entered Atareb and saw that all the houses and shops were abandoned, everything was destroyed and burned," al-Omar said.
During a visit to Atareb last August, CNN journalists saw a virtual ghost town of ruined buildings devastated by months of fighting between regime forces and rebels.
"I never thought the situation was so bad, I just saw things on TV," al-Omar continued as his eyes filled with tears. "When I saw these things with my own eyes I cried, 'How can Bashar al-Assad do this? ... I apologize to the Syrian people, because I worked at some point with this butcher and killer regime."
It was a tearful, emotional apology from a Syrian who had spent years working his way into the halls of power. But his sincerity was questionable, coming from a man who admitted to spending years lying for the Syrian regime.
Journalist Ammar Cheikh Omar contributed to this report.