Police said all the suspects, the oldest being 39, confessed to the crime during interrogation.
Over 30 armed men had robbed about five banks in the town simultaneously, killing at least 17 persons, including eight police officers.
In a statement issued on Friday, April 13, police spokesman, Jimoh Moshood, revealed that phones, SIM cards and Ipads belonging to victims of the robbery were recovered from the suspects.
The police had earlier arrested seven suspects in connection to the incident.
Moshood listed the newly arrested suspects as follows:
Adegoke Shogo, 29; Kayode Opadokun, 35; Kazeem Abdulrasheed, 36; Azeez Abdullahi, 27; Alexander Reuben, 39; and Jimoh Isa, 28.
Others are Azeez Salawudeen, 20; Adewale Popoola, 22; Adetoyese Muftau, 23; Aminu Ibrahim 18; Richard Buba Terry, 23; and Peter Kuunfa, 25.
Moshood said, "The police teams engaged in massive raids of identified criminal spots/flashpoints, stop and search operations, visibility and confidence building patrols, intelligence gathering which led to the arrest of the suspects.
"Some of those arrested also involved serious exchange of gun fire between the police and the suspects in their various hideouts.
"All the suspects during investigation confessed to the various criminal roles they played in the commission of the crime, however, investigation is being intensified to arrest other suspects still at large and bring them to justice."
The police spokesman added that two Beretta pistols, and twenty rounds of live ammunition were also recovered from the suspects.