(CNN) When Sina Ghanbari took to Tehran's streets during nationwide demonstrations at the beginning of 2018, he was speaking out against corruption, a sluggish economy and soaring fuel and food prices.

Ghanbari was detained during the protests. After being held in the so-called quarantine ward of Tehran's Evin prison for five days, he died on his 22nd birthday.

Prison authorities told his mother, Fatemeh Malayan Nejad, that her son had taken his own life. "My son called me from prison. He told me they had beaten him up," Nejad tells CNN. "It's a big lie that he committed suicide, and I won't rest until the truth comes out." Ghanbari's mother says she believes he was murdered.

Fatemeh Malayan Nejad holds a picture of her son Sina, who was detained for protesting and died after five days in custody. Courtesy of Fatemeh Malayan Nejad/Masih Alinejad

Ghanbari is one of nine protesters who died under "suspicious circumstances" after being detained by the Iranian authorities in 2018, according to a report by Amnesty International released on January 24. The rights group also says that at least 26 protesters were killed on the streets, and more than 7,000 dissidents of the regime were arrested throughout the year. Of that figure, 11 lawyers, 50 media professionals and 91 students were detained arbitrarily.

The Iranian government has not responded to CNN's request for comment.

But Iran's protest movements show little sign of abating. As security forces step up their crackdown, dissidents have continued to stage demonstrations. Rather than quashing dissent, experts say, Iran's repression may have emboldened activists.

"Protesters feel they have nothing to lose," says Mansoureh Mills, Amnesty International's Iran researcher. "In the past year, we've seen thousands of workers across the country in anguish because they haven't been paid for months and are struggling to feed their families."

"You only have to watch videos of these protests on social media and listen to workers calling out, 'We do not fear prison because we have nothing more to lose' to understand how emboldened they have become," Mills added.

The wave of protests in 2018

The economic protests of December 2017 and January 2018 were the largest display of public discontent in Iran since the 2009 Green Movement , when millions took to the streets to demonstrate against alleged election fraud.

But while the Green Movement attracted far larger numbers, the geographic scope of the 2017 and 2018 protests caught authorities by surprise. The demonstrators were largely from outside the capital. They gathered in major northeastern cities -- such as the conservative stronghold of Mashhad -- and in the provinces. They also largely hailed from the country's working class. Both demographics were long considered centerpieces of the regime's popular base.

"What was noteworthy was their geographical spread," says Mohammad Ali Shabani, Iran Pulse editor at Al-Monitor. "Equally noteworthy was the lack of elite backing: beyond general statements of sympathy for demands such as more jobs and lower consumer prices, no major political camp sided with the protesters."

Despite the regime's violent response to the initial 2017 and 2018 demonstrations, individuals and coordinated groups of dissidents continued to publicly demand political and social reforms throughout 2018.

As Iran's economic crisis deepened, peaceful demonstrations were held during July and August which authorities dispersed by using live ammunition, tear gas and water cannons, according to Amnesty.

Teachers in Tehran held protests in October and November which resulted in 23 arrests and eight prison sentences. By the end of the year, 467 workers, including truck drivers, factory workers and teachers, had been questioned by authorities or subjected to torture and other ill-treatment.

"(The crackdown) is the worst we have witnessed over the past decade," Raha Bahreini, Amnesty International's Iran researcher, tells CNN.

A few brave women

Perhaps the highest-profile social movement to gain momentum during 2018 were the protests against Iran's compulsory hijab law.

On December 27, 2017, Vida Movahedi, a 31-year-old Iranian mother, climbed atop a utilities box on one of Tehran's most crowded streets and silently waved a white headscarf on a stick. She stood unveiled, her long hair flowing in the breeze.

Movahedi was arrested a few hours later, but a photograph of her solitary act went viral. The image helped galvanize exiled Iranian Masih Alinejad's "White Wednesdays" social media campaign. The movement encourages people to protest against the mandatory headscarf law by wearing white on Wednesdays or going out unveiled.

Vida Movahedi stands on a telecoms box on a Tehran street after removing her headscarf and holding a stick to protest against the country's compulsory hijab rules.

Through her campaign, Alinejad receives pictures and videos of these demonstrations. She then shares them on her social media accounts, which have a combined following of more than 2.3 million. Within weeks of Movahedi's act, women across the country were filming themselves unveiled on busy streets in a show of solidarity.

By the end of 2018, at least 112 female activists had been arrested or detained, according to Amnesty. Despite the arrests, the White Wednesdays movement continues today and shows no signs of subsiding.

Shaparak Shajarizadeh, 43, an active member of the movement, was arrested three times in 2018 before eventually fleeing to Turkey, and then seeking asylum in Canada. She was first detained on February 21 for sharing a video of herself online mirroring Movahedi's demonstration.

"I got beaten in the morality and security office, then they sent me to solitary confinement in jail. I was on a hunger strike for one week, then I got released," Shajarizadeh tells CNN. "After that I received threatening calls -- they told me to stop posting my pictures online and speaking about the compulsory hijab laws."

Nasrin Sotoudeh, a prominent human rights lawyer and women's rights defender in Iran, took up Shajarizadeh's case. While awaiting sentencing, Shajarizadeh was illegally detained by authorities again in March and May. She says she was tortured, threatened and thrown in Evin prison.

"I was accused of corruption and prostitution for posting pictures without my hijab online," Shajarizadeh says. "They told me to drop Nasrin Sotoudeh as my lawyer -- threatening to charge me with national security charges against the country if I kept her."

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Shajarizadeh was sentenced to 20 years in prison, 18 of which were suspended. Sotoudeh was herself arrested on June 13, 2018, for defending several anti-compulsory hijab protesters. She faces national security-related charges which could see her sentenced to more than a decade in prison.

According to the Center for Human Rights in Iran, she is denied visits by her family. On January 23, Sotoudeh's husband, Reza Khandan, also a prominent human rights lawyer, was arrested and sentenced to six years in prison for security-related charges. Both are now appealing their charges.

Shaparak Shajarizadeh stands unveiled in an Iranian town waving a white scarf on a stick, as part of the anti-compulsory hijab protests of 2018.

US intentions

Throughout 2018, senior US administration officials -- including President Donald Trump and Secretary of State Mike Pompeo -- repeatedly aligned themselves with Iranian protesters to further isolate the regime.

During the wave of demonstrations in January, Trump tweeted , "The people of Iran are finally acting against the brutal and corrupt Iranian regime." The President then warned that the US was watching closely before declaring, "it's time for a change."

Pompeo seemed to take a personal interest in the anti-hijab demonstrations, and on at least two occasions in 2018 tweeted images of Vida Movahedi's protest. In June, he even posted a graphic of Movahedi next to a photo of Iran's Supreme Leader Ali Khamenei, with the slogan "Iranian people deserve respect for their human rights" written over the image. The State Department also tweeted several messages in support of women's rights in Iran -- all written in Farsi.

5,000 Iranians arrested in January's protests. 30 women jailed for protesting the hijab. Hundreds of Sufi dervishes, dozens of environmentalists, 400 Ahwazis, 30 Isfahan farmers -- all imprisoned by #Iran's criminal regime. Iranian people deserve respect for their human rights. pic.twitter.com/evH3lmfSjl — Secretary Pompeo (@SecPompeo) June 21, 2018

During a speech at the Heritage Foundation in May 2018, Pompeo laid out how the US planned to proceed with Iran following the withdrawal from the 2015 nuclear agreement. Addressing the Washington crowd he said: "The Iranian people will get to make a choice about their leadership. If they make the decision quickly that will be wonderful.

"If they choose not to do so, we will stay hard at this until we achieve the outcomes that I set forth," Pompeo continued.

The cumulative effect of these actions has led Iran's President Hassan Rouhani to accuse the administration of openly agitating for regime change. "Reducing the legitimacy of the system is their final goal," Rouhani said in a speech on Iranian state TV broadcast in October.

What to expect in 2019

Although more Iranians are publicly airing their social and economic grievances, the lack of organized political opposition within Iran has left analysts confident that the protest movements pose no serious threat to the regime.

"We can expect more protests in coming months as the economic situation deteriorates, but it's hard to predict where they may lead on account of their lack of organization, formulation of clear and unitary demands, and elite buy-in," says Al-Monitor's Shabani.

US Ambassador John Limbert, who was held captive during the 1979 hostage crisis and served as Deputy Assistant Secretary of State for Iran in 2009, is confident the regime will prevail. "In the Islamic Republic, the authorities always feel threatened," says Limbert. "They will do what they need to do to stay in power. If that requires brutality, so be it. If it means flexibility, they'll try that."

"The same men's club has run things since 1979. Although age is catching up with them, they'll hold on as long as they can. It's clear that they are mostly clueless about the realities of their own society, where people are creative, engaged, and well-educated," Limbert tells CNN.

On January 29, the Worldwide Threat Assessment for 2019 was released by the US Director of National Intelligence Dan Coats. "We assess that Tehran is prepared to take more aggressive security measures in response to renewed unrest," the document says.

As the regime looks set to dig in its heels in 2019 though, so too do some of the protesters.

One 38-year-old from Mashhad who took part in both the 2017 and 2018 protests and demonstrations in support of the White Wednesdays movement, tells CNN that despite being beaten, threatened and thrown in prison, he has no plans to remain silent in 2019. "I will keep protesting until the removal of the compulsory hijab law, and until there's freedom for Iranian people from this despotic religious regime," says the protester, who declined to disclose his name for security reasons.

Amnesty International's predictions for the year ahead echo his comments. "Iran is in the grip of an unprecedented crisis that is rooted in a confluence of severe political, economic, environmental and human rights problems," says researcher Bahreini.

"We can, therefore, expect that protests against poverty, inflation, corruption and political authoritarianism will grow in the country."