Even to a country inured to violence, the images were shocking. A man on a motorbike pulled up next to a car window and fired three shots at Tara al-Fares, killing her on a Baghdad street.

The daylight assassination, captured by a surveillance camera, was both brazen and familiar to Iraqis who lived through the civil war and painful decade since.

Yet it was also shockingly distinctive; the body slumped in the car seat was not a politician, official, insurgent or warlord. She was a former beauty queen; a young woman with both profile and attitude, one of four high-profile Iraqi women to have been killed across the country in quick succession.

The four were unknown to each other, but their lives – recently at least – had shared common themes. All had a public presence and a voice that had unsettled elements of Iraqi society, which has retained rigid views on how women should behave, even as relative freedoms have crept into a still conservative culture.

To reveal one such trait in post-war Iraq is daring, many Iraqi women say. To proudly showcase both can be reckless.

The effervescent Al-Fares has become a lightning rod for all four deaths, and sparked a rare public discussion in Iraq about how far women have come in the 15 years since the US invasion, the proponents of which had vowed that civic freedoms and individual liberties would somehow emerge from the ensuing chaos.

The death of Al-Fares, 22, last Friday, followed the killing of Suad al-Ali, a women’s rights activist in the southern city of Basra, who was gunned down as she walked to her car. In August, two more Iraqi women, Rasha al-Hassan and Rafifi al-Yasiri were killed one week apart. Both worked in beauty clinics.

Rasha Al-Hassan was director of the Viola Center for Iraqi Medical Beauty Photograph: veolla.center/facebook

Iraq’s acting prime minister, Haider al-Abadi has said that that the deaths are not random events and has pledged to hunt down the attackers. Iraqi women have gone further. Zainab Salbi, an Iraqi who leads the institute Women for Women International in Washington said “Women are being hit left right and centre. Everywhere. We are living in the modern witch-hunt.”

Al-Fares did not fit the mould. A divorced single mother who had married at 16, she had swayed her way into Iraqi homes with short skirts and makeup on social media platforms. She had 2.7 million Instagram followers and was popular on Twitter, Facebook and YouTube. All are hugely popular in Iraq, where living vicariously remains acceptable – but maintaining a high profile brings danger, especially for women.

“We can go to Lebanon and dress how we want,” said Hadeel Muthanar, who identifies herself as a socially conservative 28-year-old from east Baghdad. “Even Iraqi men will look the other way there. But to do the same in Baghdad is shameful. This is two-faced, but it’s the way we are.”

Al-Fares, born to a Lebanese Shia mother and an Iraqi Christian father, made little attempt to bow to the norms that many expected of her. Her profile was created as a challenge to double standards that many in Iraq complain about but remain unwilling to tackle.

The reaction to Al-Fares’ death on social media was part sympathetic and part scathing, a reflection of how what she stood for had polarised Iraqis. A state media employee was sacked after labelling Al-Fares a “whore” on social media posts.

In August, the death of Dr Rafif al-Yasiri, a renowned plastic surgeon also created ripples. The 32-year-old was labelled the “Barbie of Iraq” and spoke regularly of women gaining independence by changing their appearance. Iraqi officials claimed she died of a drug overdose. One week later, popular beautician, Rasha al-Hassan, was found dead inside her home. Her cause of death remains suspicious.

“The enormous amount of messages I noticed on social media have made me sick,” said Zainab, 39, who added that the recent killings had made her afraid to reveal her surname. “They say: ‘They deserved what they got because of their actions.’”

“People are accusing these girls of abusing their own freedoms. But it is the understanding of freedom that is being abused. The families are being forced to defend themselves instead of mourn their loss and this is wrong.

Rusul Kamil a female activist and specialist on gender- based violence, said: “I think that what happened to these girls is considered as a threat for all Iraqi women and girls who want to live their lives freely, regardless of their ethnicity, religion and roles. Diversity and difference became a risky approach for all women.”

Sura Ahmed, a Baghdad university student agreed. To her the deaths are unlikely to change attitudes which still resent “untraditional women”.