The man is known as Abdurahman Mohamed Kuno alias Gamadhere alias Dulyadeen or Sheikh Mahamad.
The initial Sh5 million bounty was raised to Sh20 million after images of the savagery and brutality meted on the students emerged.
Gamadhere is a former madrassa teacher in Garissa.
He is a suspected senior al Shabaab Jabha (military) leader in Lower Juba and Kenya.
Gamadhere, who was revenging the killing of his friends, is believed to have been aided by two local youth who conducted surveillance on the university.
In December last year, police circulated pictures of two wanted al Shabaab suspects, one of them Gamadhere.
They offered Sh2 million to anyone who would provide information leading to their arrest.
Gamadhere, a Garissa resident, is believed to be behind the recent attacks in Mandera and is currently in charge of external operations against Kenya.
Police had earlier released his profile, including the fact that he has three wives. One of the wives is in Huda near Ras Kamboni.
His second wife lives in Garissa, while his third wife, Sultano Feysal Dubat, resides in Bulla Iftin, near Bulla Iftin Secondary School, in Garissa and hails from the Harun Clan.
His mother is Ralia Mohamed Wardere alias The Iron Lady.
His siblings include Abdi Yussuf Ali Adan alias Abdi Mulla, an al Shabaab leader who accidentally shot himself with his own pistol while demonstrating safety precaution techniques to new recruits in Kismayu. He survived the accident.
Hussein Mohamed Ali alias Hussein Marerey, an employee of the Wajir South Development Agency.
Abdi Ismail Ali is Gamadhere’s half-brother.
Gamadhere worked for Al-Haramain Foundation and later was a teacher and principal of Madarassa Najah in Garissa. He later joined al Shabaab.
Gamadhere claimed responsibility for the November 22, 2014, bus attack in Mandera in which 28 people were killed.
Source: The Star Daily