Ceremonies marking the one-year anniversary of the abduction of more than 200 Nigerian school girls by the terror group Boko Haram were to be held in Nigeria and across the world Tuesday, as the fate of most of the girls remained a mystery.

A procession will be held in the Nigerian capital of Abuja featuring 219 marching girls, representing each of those who are still missing. Similar marches have been planned in other world capitals, including Washington. 

The abduction of the 276 students from the Government Secondary School in the northeastern town of Chibok drew worldwide attention to the Islamist group and its ongoing conflict with the Nigerian government, at one point spawning the trending Twitter topic #BringBackOurGirls. But as the weeks and months passed, global attention drifted to other battlegrounds of the war on terror, such as the fight against ISIS, to whom Boko Haram recently pledged allegiance.

That silence has spread to Nigeria's own government, which has released precious little information about any action to free the girls. On Monday, the BBC reported that a Nigerian woman said she had seen 50 of the girls three weeks earlier in the northeastern town of Gwoza, until recently the terror group's operational base. The woman said she saw the girls in Islamic attire, being escorted by militants. 

"They said they were Chibok girls kept in a big house," the woman said. "We just happened to be on the same road with them," she added.

Nigeria's military recaptured Gwoza from Boko Haram last March, but there has been little information about what, if any, traces of the girls were found there. Boko Haram leader Abubakar Shekau has said the girls have been converted to Islam and married off. Relatives of the girls feared the militants had used them as bartering goods and sex slaves.

Nigerian President Goodluck Jonathan came under heavy criticism for not doing more to try and free the girls, most of whom range in age from 16 to 18. Jonathan was defeated in a presidential election last month by former military dictator Muhammadu Buhari. Buhari, who will be inaugurated in May, has committed his government to do "everything in its power to bring them home", but also sounded a note of warning. 

"We do not know if the Chibok girls can be rescued," he told the BBC. "Their whereabouts remain unknown. As much as I wish to, I cannot promise that we can find them."

The Chibok abductions, while shocking, were not out of character for Boko Haram. Amnesty International, in a report timed to the anniversary of the Chibok abductions, said Tuesday that at least 2,000 women and girls have been abducted by the group since the start of 2014. The report said many of the abductees had been forced into sexual slavery, or trained to fight alongside the group. Amnesty International estimates that Boko Haram has killed at least 5,500 civilians since the start of last year.

Amnesty's findings have been supplemented by a United Nations report that says Boko Harma often forces women and girls it seizes into marriages that entail repeated rapes.

"Forced marriage, enslavement and the 'sale' of kidnapped women and girls are central to Boko Haram's modus operandi and ideology," it said. "Abducted girls who refuse marriage or sexual contact within marriage have faced violence and death threats."

The report listed Boko Haram as one of 45 groups that are "credibly suspected of committing or being responsible for patterns of rape" in conflict.

Meanwhile, the families of the girls are left to wait and hope for a miracle.

"At night I sometimes wake and wonder, and pray to God to deliver the girls," the mother of one of the abductees, known only as Esther, told the BBC. "Whenever I want to eat what comes to my mind is, has my daughter eaten?" 

The Associated Press contributed to this report.