Many analysts, however, expressed skepticism, saying the political cost of freeing the former leader, who was widely hated for widespread abuses and repression during his 29 years in power, could keep him in jail.
Leading rights campaigner Nasser Amin and rights lawyer Hoda Nasrallah said they did not expect Mubarak to be released, citing the country's delicate political and security situation as well as past incidents when authorities brought up new allegations to prevent his release.
Amin complained that Egypt's penal law, which dates to the 1930s, has no adequate provisions to allow the conviction of perpetrators of crimes like ordering or failing to prevent the killing of protesters. Already, the overwhelming majority of court cases brought against policemen charged with killing protesters have ended in acquittals or suspended sentences.
"His release or detention will be a decision that weighs political and security conditions in the country," said Nasrallah.
Freeing Mubarak during one of the worst bouts of turmoil since his ouster would be a huge risk for the military-backed government. It could lend credibility to allegations that the mass protests that preceded the July 3 coup that toppled Egypt's first democratically elected leader were the work of Mubarak-era figures searching for a way to reinstate the former regime.
Last week, the military raided two protest camps of Morsi's supporters in Cairo, killing hundreds of people and triggering a wave of violence that has left at least 1,000 people dead.
Human Rights Watch, in a report released Monday, accused Egyptian security forces of using excessive force when they moved to clear the larger of the two camps. The New York-based group said the assault amounted to the "most serious incident of mass unlawful killings in modern Egyptian history."
It called on authorities to reverse a recent decision authorizing the use of deadly force by security forces when they come under attack or when key government facilities are assaulted.
The Sinai Peninsula has long been wracked by violence by al-Qaida-linked fighters, some who consider Morsi's Brotherhood to be too moderate, and tribesmen who have used the area for smuggling and other criminal activity.
However, Islamic militancy has been on the rise in the area, with almost daily attacks targeting security forces since Morsi's ouster.
Monday's attack targeting the police officers took place near the border town of Rafah in northern Sinai. A few hours later, militants shot to death a senior police officer as he stood guard outside a bank in el-Arish, another city in the largely lawless area, security officials said.
There was no immediate claim of responsibility for either attack. The United States condemned the slaying of the police officers and repeated its commitment to help Egypt combat terrorism in Sinai. U.N. Secretary-General Ban Ki-moon also denounced the attack.
"The Sinai Peninsula remains an area of concern, and the current situation in Egypt has not improved the situation," State Department spokeswoman Jen Psaki told reporters in Washington. "The United States continues to support Egypt's ongoing efforts against terrorism and growing lawlessness in the Sinai, and we continue to cooperate with Egypt in these efforts."
The attacks came a day after security forces killed 36 detainees during a riot on a prison-bound truck convoy north of Cairo. The killings came as police fired tear gas to free a guard who was trapped in the melee, security officials said.
On Monday, the government ordered an inquiry into the deaths, which it blamed on armed men allegedly trying to help the 600 Muslim Brotherhood detainees escape. It gave no details.
The Brotherhood blamed military chief, Gen. Abdel-Fattah el-Sissi, and the interior minister for Sunday's killings. The group also called for an international inquiry into the deaths.