While a "proof of life" video has brought fresh hope to the parents of more than 200 abducted schoolgirls, it is also a sign of the formidable obstacles that will make it increasingly difficult to liberate them from Boko Haram.
Only 15 of the abducted Chibok girls were visible in the newly released video this week. It reinforces the belief of many analysts that the girls have been scattered across Boko Haram's territory in northern Nigeria and perhaps even in neighbouring countries.
Under heavy pressure from the Nigerian military, the Islamist radicals of Boko Haram are believed to have fragmented into isolated cells and groups, each of which may hold a few of the Chibok schoolgirls. This has vastly complicated the precarious process of rescuing them or negotiating their release.
After losing much of its territory to the Nigerian army, Boko Haram has been unable to replenish its supplies as swiftly as before. Driven by hunger, its fighters have raided villages and farms for food. This is one probable explanation for the growing reports of ransom negotiations between Boko Haram representatives and the Nigerian authorities.
But the ransom demands are reported to be high – probably in the millions of dollars – and the Nigerian government is reluctant to hand over huge sums of money for an uncertain gamble, especially if the Boko Haram negotiators are divided and their control of the girls is unclear. Previous negotiations and ransom demands have led nowhere, adding to the government's skepticism.
This, in turn, has fuelled tensions between President Muhammadu Buhari and the Nigerian activist movement known as Bring Back Our Girls, which holds daily vigils for the girls.
Before his election last year, Mr. Buhari had promised to do everything possible to free the girls. When he was sworn into office last May, he repeated the pledge. "This government will do all it can to rescue them alive," he said in his inauguration speech. "We cannot claim to have defeated Boko Haram without rescuing the Chibok girls and all other innocent persons held hostage."
It was a stirring declaration. But a few months later, in December, he announced that Boko Haram had been "technically" defeated, even as he admitted that the government had no idea where the kidnapped girls were located. He met the Chibok parents in January, but his remarks to them were terse and scripted, the parents said.
On Thursday, when the Chibok activists tried to march on Mr. Buhari's presidential villa in Abuja, his officials were unwilling to let them reach even the villa gates. Police formed a barricade and turned them back, several hundred metres from the gates, leaving them stranded on the edge of a busy thoroughfare.
In a statement on Thursday to mark the second anniversary of the Chibok kidnapping, Mr. Buhari said he understood the "torment, frustration and anxiety" of the parents. He said he shared their pain. But he also asked the parents to "exercise patience" as his officials explore "all possible options" for the safe return of the girls.
The activists from Bring Back Our Girls said they were "puzzled" by Mr. Buhari's repeated claim that the government lacks "credible intelligence" on the location of the girls. They said the government is failing to collect key evidence and intelligence from other civilians who have been rescued from Boko Haram over the past year.
"We are extremely dissatisfied with the unprofessional manner in which our rescued compatriots are treated," they told a press conference on Thursday.
"The incredible wealth of information that victims of terrorists can offer our security forces is being lost in the current undefined and ineffective approach."
A report on Friday in Daily Trust, a Nigerian newspaper that specializes in northern news, gave a further glimpse of the obstacles to the rescue efforts. The Chibok schoolgirls "are being held by different Boko Haram commanders, who are also making conflicting demands," the newspaper said.
At least three different Boko Haram groups have approached the government with varying demands, it said.
"The government is in a dilemma because it wanted all the girls released at once but the militants said they can only be released in batches of 10," the newspaper said, quoting an unnamed source.
To make matters worse, Nigeria's security services are competing with each other for control of the negotiations, which is "frustrating" the process, it said.
To help Nigeria search for the abducted girls, the United States has provided military advisers, police officers, intelligence data and satellite imagery. But this information has also revealed the difficulties that continue to hamper the search.
After the kidnapping, the girls were "moved to some very, very isolated places," said General David Rodriguez, commander of the U.S. military's African command.
"Boko Haram operates out of some terrain that is pretty tough to get at and get to," he told a briefing at the Pentagon this month. Meanwhile, in the two years since the kidnapping, 18 of the Chibok parents have died without seeing their daughters.
Some of the parents were killed by Boko Haram. Some died of other causes. And some have succumbed to stress-related illnesses as they endured the heartache of not knowing the fate of their daughters.