Two Algerians who accompanied Frenchman Herve Gourdel just before militants kidnapped and beheaded him are under house arrest while a judge investigates whether they were involved in the abduction, two security sources said on Wednesday.
The two men were among five Algerians who went with Gourdel on a mountain hike last month before he was taken by militants who killed him to punish France for its military intervention against Islamic State fighters in Iraq.
Two Algerian sources said the men had been put under judicial control, a form of house arrest which means they must report to authorities during a judge's investigation.
Algerian officials were not immediately available to confirm the reports, and details of the investigation into who had accompanied Gourdel on his hike into the mountains east of Algiers while on holiday were unclear.
Algeria's justice minister had said on Tuesday several members of the militant group involved in the crime had been identified, without giving details of those suspects.
Since Gourdel was kidnapped, Algerian security forces have been scouring the remote mountains with helicopters and troops, in what one local resident described at the time as looking like a military invasion.
But the area is mostly remote, densely forested mountains where a small group of militants would be afforded easy cover especially for a small group of experienced fighters who spent years there during Algeria's 1990s civil war.
"It looks like finding Herve Gourdel's body might take some time given the geography of the area where he was kidnapped," another security source told Reuters.
The Frenchman's kidnapping was one of the first abductions of a foreigner by militants in Algeria since the North African country ended that decade-long with Islamist fighters when around 200,000 people were killed.
Algeria's Caliphate Soldiers group, which pledges loyalty to the Islamic State militants targeted by U.S. and coalition air strikes in Iraq and Syria, released a video statement a week ago saying it beheaded Gourdel.
The group's leader is a veteran of the civil war when militants often massacred villages and cut victim's throats in a brutal conflict with the Algerian military.
The kidnapped Frenchman, a mountain guide and photographer, had been on holiday with local associates to hike in the mountains east of Algiers in an area once known as the "Triangle of Death" during the darker years of Algeria's conflict.
Kidnappings have been known in the area, mainly local businessman who have been targeted by militants for ransom.
The Caliphate Soldiers released a new video statement on Tuesday showing around 30 fighters reaffirming their allegiance to Islamic State in Iraq, in a breakaway from North Africa's al Qaeda branch, Al Qaeda in the Islamic Maghreb or AQIM.
The recording posted jihadi social media shows the Jund al-Khilifa, as the Caliphate Soldiers are known in Arabic, showing one Algerian commander speaking to the small group of men, some carrying automatic rifles, in a densely wooded area.
They made no reference to Gourdel's execution or any threats of further attacks.
Gourdel's kidnapping occurred after Islamic State urged the group's followers to attack citizens of the United States, France and other countries that joined the coalition to destroy the ultra-radical Islamist movement.