Lagos: When Dauda Yama retrieved his mobile phone from a neighbour's house in January this year, he noticed a missed call from his daughter Saratu who had been missing for almost two years.
The last time he spoke with Saratu was on April 14, 2014, when she rang to say men from the group Boko Haram had loaded her and her classmates from the Government Girls' Secondary School in Chibok in northeast Nigeria onto trucks.
Attempts to reach her again failed and two years on, 219 girls abducted that night remain missing, despite a global campaign #bringbackourgirls involving celebrities and U.S. first lady Michelle Obama calling for them to be found.
The students are among an estimated 2,000 girls and boys abducted by the Boko Haram since the start of 2014, with many of those abducted used as sex slaves, fighters and even suicide bombers, according to an Amnesty International report.
But when Yama returned the missed call that evening, a man answered. Yama hung up and rushed to the home of Yakubu Nkeki, chairman of the Association of Parents of the Abducted Girls from Chibok.
"He asked me what he should do," Nkeki, 58, a schoolteacher, whose 17-year-old adopted daughter Maimuna Yakubu Usman is among those missing, told the Thomson Reuters Foundation.
Nkeki took the phone and redialled the number that was again answered by a man who said the phone belonged to his wife.
Reporting the matter to any of the armed personnel around Chibok was out of the question so instead they informed a campaigner with the Bring Back Our Girls group, which advocates the return of the missing girls "now and alive".
"We don't know who to trust," said Nkeki who has received physical threats for his efforts to keep the abduction of the Chibok girls in the headlines and the government's sights with the abduction becoming a political issue for Nigerian leaders.
Providing counsel to parents of the missing Chibok girls is part of Nkeki's role as chairman of the association. He also checks up on the parents to see if they need help at all.
"I check if they have food items or if someone is seriously sick," he said. "If there is any issue, I call the committee members."
Some months ago, for example, the association received a donation of 128 bags of corn from a missionary group. The association decided to give three bags to one parent to sell and raise money for medicine for his son who was bitten by a snake.
Nkeki said he had not intended to become a leader for the parents but was catapulted into the role when he tried to rally families into action after the abduction.
Under his lead, and frustrated by a lack of official action, the parents formed a team to search the Sambisa forest for missing girls the day after the abduction, finding scarves and other items along a trail until heavy rain forced them back.
Nkeki then organised a meeting of parents in his village of Mbalala, calling for a peaceful demonstration and seeking media coverage to get the word out, with his initiatives prompting the parents to appoint him as their leader.
It was Nkeki's efforts that ascertained exactly how many girls were missing after the school said the Boko Haram had razed all records. He cycled from village to village for two weeks with pen and paper to build a register.
"I got the names of the girls, their pictures. I asked for proof. They showed me their daughters' books so that I could get the exact name the girl used in the secondary school," he said.
His census revealed the number of girls abducted was 276 but 57 were able to escape as the trucks took off and came home.
But the attempts to rally parents were not always welcome.
Nkeki said some parents refused to have anything to do with the parents association and he has been harassed and arrested by armed forces personnel, displeased with his media appearances and efforts to keep the missing Chibok girls in the news.
Former Nigerian President Goodluck Jonathan was criticised for his slow reaction to the Chibok kidnappings, which was seen by some as indicative of his response to Boko Haram, which at its strongest held large swathes of northeastern Nigeria.
President Muhammadu Buhari, who defeated Jonathan in an election last year, ordered a new investigation into the abductions in January.
"My family is afraid for me. Even my uncle's wife whose daughter was abducted, the one I adopted, said to me that she does not want to lose her daughter and then also lose me," said Nkeki.
But despite Nkeki's efforts, his daughter and the other girls are still missing, with the parents desperate for any leads that could help locate their daughters.
Hopes were raised earlier this month when a suspected female suicide bomber who claimed to be one of the missing Chibok girls was arrested in northern Cameroon.
But official investigations revealed the 12-year-old girl was not from Chibok but abducted from Bama in northeastern Nigeria by Boko Haram a year ago.
Nkeki and Yama dialled Saratu's number a few more times after the initial success but the line repeatedly went dead. However, Nkeki says it rang when Yama tried again in February.
"The man warned him never to call his wife's number again. He said if he is not careful, he will lose his life," he said.