An Iraqi pharmacist and her family were killed after an intruder broke into their home late on Tuesday, security officials said.
Sheelan Dara, who came from an affluent Kurdish family, took part in anti-government protests during the uprising in last October.
"Unidentified gunmen stormed a house in Al Mansour district, west of Baghdad, on Tuesday evening, and slaughtered the pharmacist Sheelan Dara, and her parents,” Baghdad police chief, captain Hatim Al Jabri, said.
The intruders stole valuables from the house as they fled, Captain Al Jabri said, as authorities opened an investigation into their killing.
Preliminary data indicated that it was "motivated by theft” he said, without further details.
Medical reports found that Ms Dara was strangled while her parents were brutally stabbed, Ali Al Bayati, a member of the Iraqi Human Rights Commission, told The National.
“It is another sign of weakness of the security system and absence of any deterrent steps to stop such crimes,” he said.
The government needs to be more serious and must start an investigation which hold the perpetrators to serious account, he said.
“This is becoming a daily story and we are just counting the numbers,” Mr Al Bayati said.
Activist Tariq Al Husseini believes the attackers deliberately targeted Ms Dara.
“The purpose of the attack was to kill Sheelan who had been active in supporting popular protests against the ruling political class,” he said, adding that this has happened with a dozen others.
“Sheelan was one of the well-known young faces in Tahrir Square,” he said.
In recent months the country has witnessed an increase in attacks against civil and human rights activists, including Riham Yaqoob, a doctor from Basra.
Ms Yaqoob was a doctor and female activist in Iraq who became the face of many local anti-government and anti-corruption protests.
She died after being shot in her car while in the city of Basra. Her killing was the third of a series of attacks on activists in a week.
Tahseen Osama was killed one week before Ms Yaqoob. His death pushed protesters to take to the streets to demand the authorities uncover those responsible.
Many human rights activists are becoming concerned over the growing number of these attacks.
"How long will these crimes continue against Iraq?! I urge Prime Minister Mustafa Al Kadhimi to open an investigation into Sheelan's case," Ali Al Bashir, civil society activist, said on Twitter.
Mr Al Bashir called on Iraqis to launch an online hashtag demanding justice for Sheelan and her family.