Updated

Egypt's police are coming under withering criticism as signs mount that officers not only fired birdshot at a young mother during a peaceful protest last weekend but then also hampered efforts to save her life by ignoring pleas to let an ambulance take her away.

According to witnesses and rights lawyers who spoke to The Associated Press on Tuesday, police also prevented anyone from trying to help 32-year-old Shaimaa el-Sabbagh after she was shot.

El-Sabbagh, a mother of a small boy, died on Saturday after birdshot fired by police hit her in the head during a rally she took part in — a small gathering of about 30-40 protesters from a leftist political party — at a downtown Cairo square, according to the witnesses.

The protesters intended to lay wreaths at the nearby Tahrir Square, the epicenter of Egypt's 2011 uprising that ousted autocrat Hosni Mubarak. The flowers were in memory of protesters killed during the uprising four years ago.

As the gathering got underway, Mohammed Fahmy from the leftist Popular Alliance party approached the officer in charge to explain their plan, according to the witnesses and lawyers.

Within minutes, without warning, the birdshot and tear gas came.

"The commander made a telephone call, then arrested Mohammed Fahmy and gave the order to fire tear gas and birdshot," said Zohdy el-Shamy, a senior party official who was also at the rally. "We did not chant against the police or the regime and we showed no intention or capability to use violence."

Egypt's top prosecutor has ordered an investigation into el-Sabbagh's death but activists say a statement by his office may have pre-determined the probe's findings by accusing the protesters of resisting and attacking the police.

Interior Minister Mohammed Ibrahim has vowed to personally hand over for trial any policeman found to be behind the killing, but insisted in a televised news conference Monday that his force uses only tear gas when faced with unarmed protesters.

El-Sabbagh's killing has struck a nerve with Egyptians, mostly because of the wide distribution on social media of images of her after she was shot, blood running down her face as she was lifted off the ground by a colleague.

Her death also has stoked anger over the perceived brutality of the police and called into question the validity of a law adopted in 2013 that bans street protests without prior permits.

President Abdel-Fattah el-Sissi, a general-turned-politician whose focus is on the economy and fighting an Islamist insurgency, has repeatedly defended the law.

"Her death has given people a wake-up call and forced many to reconsider where they should place their political sympathies," said rights lawyer Mohammed Abdel-Aziz, who knew el-Sabbagh.

But, he added, with Egypt deeply politically fractured and in the absence of a free media, it's unlikely to spark another uprising along the lines of the 2011 mass movement.

Four of el-Sabagh's fellow protesters and a lawyer who was at a restaurant meters (yards) away at the time of the shooting came forward to testify to prosecutors that police fired the birdshot and that officers denied repeated requests by other protesters to allow an ambulance through their lines to take her to hospital or help her at the scene.

One of the four, Sayed Abulela, said he and others struggled to carry el-Sabbagh to safety in side streets and tried in vain to get a taxi or a private car to take her to hospital.

When they screamed at police officers to allow an ambulance through, Abulela said, he was arrested along with another protester and a doctor who happened to be at the scene and was trying to help.

"They took me away ... as she held on to our hands, her final hold on life," he added.

El-Sabbagh was pronounced dead on arrival at a hospital she was brought to in a private car.

The witnesses have since been released, an unusually lenient measure given Egypt's security climate but they face a slate of charges, including taking part in an illegal protest, assaulting police and cutting off a public road.

One of the last images of el-Sabbag, shortly after she was hit, shows her leaning on another protester, her head, shoulders and face bloodied and her eyes looking in the distance.

"Perhaps she was so sure of her departure at that moment, that all that was left for her was to think of what they will tell her boy ... after all the kind lies about what happened cease to be convincing," Bilal Fadl, a prominent author and a dissident, wrote in a column mourning her death.

The following day, at least 23 people were killed in Egypt, including 3 policemen, in violent protests as Egyptians on Sunday marked the fourth anniversary of Mubarak's ouster.