Despite the stepped up fight against Al Shabaab terrorists in Somalia and at home, Kenya's security services say that some Kenyan high schools and universities have become a place of radicalization.
Abdirahim Abdullahi had dropped out of the University of Nairobi, one of the leading law schools in the country. The Kenyan-born son of a local chief in Kenya's northeastern county of Mandera, Abdullahi had disappeared from his family in late 2013, and his father reported him missing. Abdullahi resurfaced that fateful Thursday, authorities say, taking part in the massacre and was in turn killed in a shootout with Kenyan security services.
Those who join militant groups are largely from Kenya's disadvantaged groups, youth often lured by the hope of financial help. But Abdullahi is believed to be an example of the militants' newer targets. Kenyan high school teachers tell CNN that -- in addition to the kids from Kenya's slums -- the terror groups are also targeting well-educated youngsters.
Government and rights groups agree, saying learning establishments in Kenya have also become recruitment grounds.
"It's clear that recruitment in schools is happening," said Hussein Khalid, director of the Kenyan human rights group HAKI Africa, which works extensively in de-radicalization in Kenya.
"Levels of recruitment into extremist movements have reached unprecedented levels. It is at its highest in the history of Kenya."
Terror in schools
Khalid says poverty is not the only force pushing young people toward terror groups. He has found that corruption and alleged abuses by security services also lead many of Kenya's youth to extremist organizations.
"Most of those joining Al Shabaab are doing so because they believe they cannot get justice locally," said Khalid. "So they then opt to join terror groups in search of what they consider to be justice."
Some of these disaffected young men, teachers and authorities say, are from Nairobi's Eastleigh High School, situated in a Somali-dominated neighborhood called "Little Mogadishu." In 2013 Kenya's National Intelligence Service put Eastleigh High School on a list of top recruitment sites in the country, according to a report leaked by local media.
Teachers at Eastleigh tell CNN that around a dozen students have disappeared over the years. Among them was one bright student who, according to two former teachers, converted to Islam, then at 18 destroyed his school certificates before vanishing in 2011 to join Al Shabaab. Then there was Hassan who teachers say dropped out of school because he could no longer afford the fees. He was wanted for links to Al Shabaab, according to police. Kenyan security services say he was later killed in a gunfight with police in a Nairobi slum.
"It's a fact that in a number of learning institutions there is evidence of recruitment going on," said Kenya Ministry of Interior spokesperson Mwenda Njoka. "It's a problem. It's a continuous struggle between the forces that are trying to recruit our young sons."
One teacher from Eastleigh, who spoke to CNN anonymously for fear of being targeted, said he was scared to open the newspapers because he feared reading that another of his students had left Kenya to join extremist groups.
"You know they are there," he said. "I would not be surprised if I saw one [in the newspaper]."
And so, Eastleigh High School decided it was time to fight back. It is now the site of a program aimed at giving students the tools they need to reject extremism.
Teaching against terror
Ayub Mohamed stands in front of his blackboard at Eastleigh High with a goal to erase the allure of Al Shabaab, a group that has staged numerous attacks in Kenya, with the massacre at Garissa University among the bloodiest.
Mohamed is one of the few teachers in Nairobi who is running a group and mentoring students specifically to prevent extremism. He is a candidate for the Varkey Foundation Global Teacher Prize this year for his work teaching against terror.
"These students are under our custody," said Mohamed. "It would be very shameful for someone from outside to indoctrinate our students when most of the time these students are under our care."
Mohamed used to teach in a school in Garissa and he dealt with issues of radicalization and insecurity even before the university attack there. In a place where students do not feel secure, Mohamed focuses on creating a safe space.
"If I don't create that safe space in the school we might find them being recruited as foot soldiers, whether as suicide bombers or brides," he said.
Some lessons are about Jihad, reading religious texts and determining the true meaning of the term, not its corrupted meaning, he says, taught by extremists to radicalize young people. He encourages entrepreneurship. He also tackles employment, poverty, and how these issues play into extremism and terror recruitment.
"We only see [themes of radicalization discussed] from the TV or when a problem happens we read from the newspapers," he said. "But for a teacher to take this conversation to the classroom it's something that has never happened."
So far, Mohamed's program does not receive substantial funding.
The Kenyan government says it is working on a plan to combat violent extremism. While it has yet to release a framework for the plan, the Ministry of Interior says civil society organizations, religious organizations, and the National Counterterrorism Centre will play a large role in stemming radicalization in all spheres, particularly in schools and universities targeting the nation's young men and women.
Mohamed notes that in today's society, where extremist groups can use so many mediums for indoctrination, such as secure messenger applications or social media to reach young people, schools and teachers have an important role to play.
"I realized we have to take this conversations to the classroom and try to use the teacher as a role model and the classroom as a safe space," he said.