CAIRO -- The Egyptian police arrested the spiritual leader of the Muslim Brotherhood early on Tuesday, hours after a court had ordered the release of former President Hosni Mubarak.
The arrest of the Brotherhood's spiritual leader, Mohamed Badie, appeared to represent a red line the police had never crossed during Mr. Mubarak's own crackdowns on the group. Taken together with the fact that the former president's release for the first time seems conceivable, the developments offered a measure of how far and how quickly the tumult shaking Egypt in recent days and weeks has rolled back the changes brought by the revolution of 2011.
The order for Mr. Mubarak's release, under a government led by former officials who worked for him, conjured the incongruous notion that he might go free even as his democratically elected successor, the Islamist Mohamed Morsi, remained in detention by the military that ousted him July 3 and installed an interim government.
In a kind of counterpoint, the arrest of Mr. Badie showed the severity of the crackdown on Islamist forces that has left hundreds dead. A private television network that supports the military leadership broadcast footage of Mr. Badie, 70, in custody, with triumphal music playing against images of him clad in a white robe and sitting on a white couch with a security officer's automatic rifle visible nearby.
In another startling turn, just as judicial authorities were setting a hearing on Tuesday to consider Mr. Mubarak's release, they announced a September trial date to hear treason charges against one of his foremost liberal critics, Mohamed ElBaradei, the Nobel-prize winning diplomat.
The charges concern Mr. ElBaradei's resignation last week as vice president of the interim government. After having initially supported the military takeover to remove Mr. Morsi as a "restart" of the transition to democracy, Mr. ElBaradei quit the government last Wednesday in protest over the bloody crackdown on sit-ins by Mr. Morsi's supporters. Although the details of the charges carry relatively minor penalties, they were widely publicized in state media and follow widespread attacks on Mr. ElBaradei for his criticism of government's crackdown. He traveled to his home in Vienna almost immediately after his resignation, and the prosecution's swift designation of a trial date appeared to be a warning that he should not return.
The incarceration of Mr. Badie, which followed the death of a son, Ammar, in clashes on Friday, was apparently designed to further deflate the Brotherhood's resolve to maintain its challenge to the military-backed government with street protests clamoring for Mr. Morsi's release.
Mr. Badie was arrested in an apartment in the northeastern Nasr City neighborhood of Cairo, news reports said, close to a mosque at the center of a six-week sit-in by Islamist supporters of Mr. Morsi at a protest camp that the security forces dispersed with gunfire and tear gas last Wednesday. Raids on that camp and another near Cairo University killed hundreds, prompting violent clashes. In recent days the protests have seemed less intense, suggesting that the Brotherhood may be retreating underground.
Its three top leaders are now in jail, along with Mr. Morsi, and after six weeks of massive protests across the country against the ouster of Mr. Morsi, demonstrations in and near the capital were becoming hard to find on Tuesday.
Charged with incitement to murder, Mr. Badie and his two deputies face trial later this month.
His arrest, made known in the early hours, came as Egyptians struggled to absorb the notion that Mr. Mubarak, overthrown as a reviled despot in February 2011, might be freed. Few legal analysts thought a release was likely, at least in the coming weeks. But under the government installed last month by Gen. Abdul-Fattah el-Sisi, they say, it is no longer a foregone conclusion that prosecutors will continue to find reasons to detain Mr. Mubarak.
Some analysts said that even the possibility of Mr. Mubarak's release, previously unthinkable, provided another sign of the return of his authoritarian style of government.
Since the ouster of Mr. Morsi, the interim government has brought back not only prominent faces of the Mubarak era but signature elements of that autocratic state, including an "emergency law" removing the right to a trial and curbs on police abuse, the appointment of generals as governors across the provinces and moves to outlaw the Muslim Brotherhood again as a terrorist threat.
The police scarcely bothered to offer a credible explanation for the deaths of three dozen Morsi supporters in custody over the weekend. After repeatedly shifting stories, they ultimately said the detainees had suffocated from tear gas during a failed escape attempt. But photographs taken at the morgue on Monday showed that at least two had been badly burned from the shoulders up and that others bore evidence of torture.
Security officers have a new bounce in their step. They are again pulling men from their cars at checkpoints for interrogation because they have beards and dealing out arbitrary beatings with a sense of impunity -- Mubarak-era hallmarks that had receded in recent years. Among civilians, even those outside the Muslim Brotherhood, fear of the police is growing.
Badr Abdelatty, a Foreign Ministry spokesman, denied any resemblance between the new government and Mr. Mubarak's. "The emergency law is just for one month and for one objective: fighting terrorism," he said, using the term that the new government applies to both civil disobedience and acts of violence by Islamist opponents of the military takeover. "The only way to fight terrorism is to apply the rule of law, and some emergency measures for just one month, to bring back law and order."
More than 1,000 Brotherhood members and other supporters of Mr. Morsi have died since Wednesday in a police crackdown, and his ouster has set off a wave of retaliatory violence from his supporters, mainly targeting churches around the country and security forces in the relatively lawless northern Sinai. In the latest episode there, militants killed 25 police officers and wounded 3 others on Monday in an attack on their minibuses. Officials said the bodies were found face down with bound hands, evidently assassinated.
Egyptian state and private television networks, all pro-government now, broadcast images of the bodies' return to Cairo, sometimes under a heading about the fight against terrorism. The Muslim Brotherhood, which has denounced the killings, held protests and marches by thousands of its supporters in Cairo and across the country, as it has every day for the six weeks since Mr. Morsi's ouster.
Some analysts said Monday that the new government was arguably more authoritarian than Mr. Mubarak's. "The Mubarak state was actually less repressive than what we are seeing now," said Shadi Hamid, research director for the Brookings Doha Center in Qatar. "In terms of sheer number of people killed, what we are seeing is unprecedented for Egypt."
But where Mr. Mubarak's supporters were diffident or self-serving, Mr. Hamid said, General Sisi "has the fervent backing of millions of ordinary Egyptians, many of whom think the army has not been sufficiently brutal against the Muslim Brotherhood."
"That is what makes this new authoritarian order much more resilient and harder to dislodge," he said.
One human rights advocate said the symbolism of Mr. Mubarak's release might help change minds. "For someone like me, it would be greatly helpful," said Hossam Bahgat, founder of the Egyptian Initiative for Personal Rights and one of only a few advocates who have questioned General Sisi's declaration that he was advancing the 2011 revolution by removing the elected president.
"It is better to end the theatrics and have some clarity," Mr. Bahgat argued, if only to convince former revolutionaries of the danger that the authoritarianism of "the Mubarak state" may be re-emerging in a different guise.
Judges have dismissed many charges originally brought against Mr. Mubarak, including directing the killing of protesters. But the previous post-Mubarak governments always made clear that they would keep finding new allegations to keep the former leader behind bars. The council of generals that succeeded Mr. Mubarak was too desperate to placate the public and preserve its own legitimacy to release him, and Mr. Morsi campaigned on promises to keep him locked up.
But the Sisi government has no such insecurity about its power, or hostility to Mr. Mubarak. Some members of political factions that had previously joined rallies for Mr. Mubarak's incarceration, or even execution, said they believed the public did not care so much anymore.
In a sign of how the Egyptian convulsions have roiled other Mideast relationships, Turkey's prime minister, Recep Tayyip Erdogan, said in a televised speech on Tuesday that he believed Israel was behind Mr. Morsi's downfall. Mr. Erdogan, a strong supporter of the Muslim Brotherhood's political ascendance in Egypt, appeared to base his accusation on what he described as previous Israeli assertions that even if the group's members had won elections, "they would not win, because democracy is not the ballot box."
Mr. Erdogan's comments drew instant attention in Israel, with top billing on several news Web sites. A spokesman for Prime Minister Benjamin Netanyahu declined to comment, under an order for government officials to remain silent on the entire Egypt question. But Yigal Palmor, the Foreign Ministry spokesman, said, "This is a statement not worth commenting on. It's nonsense."
Uzi Landau, the minister of tourism, told Army Radio that Mr. Erdogan's "statements are detached from reality."
The Obama administration also criticized Mr. Erdogan's comments. Josh Earnest, a White House spokesman, told reporters in Washington: "Suggesting that Israel is somehow responsible for recent events in Egypt is offensive, unsubstantiated and wrong."
Turkey and Israel have had icy relations for more than three years, since an Israeli raid on a Turkish-led flotilla trying to bring aid to the Gaza Strip in which nine people were killed. Under heavy pressure from President Obama, Mr. Netanyahu apologized to Mr. Erdogan in March for errors made during the raid, but in the months since, the two nations have failed to reach the promised reconciliation on issues including compensation for the families of the flotilla victims. On Monday, Turkey was included in a travel advisory as a country Israelis were advised against visiting because of "ongoing potential threats."
Given Mr. Erdogan's accusation, Mr. Landau said on Tuesday, "Without a doubt, it was a dire strategic mistake to apologize to Turkey."
David D. Kirkpatrick reported from Cairo and Alan Cowell from London. Reporting was contributed by Mayy El Sheikh from Cairo, Sebnem Arsu from Istanbul and Jodi Rudoren from Jerusalem.
This article originally appeared in The New York Times.