The Economic and Financial Crimes Commission has arrested Hassan Tukur, a former Principal Private Secretary to ex-President Goodluck Jonathan.
Tukur was arrested by operatives of the EFCC in Abuja on Monday.
Sources said he was arrested in connection with the probe into the $15 billion arms scam rocking the Jonathan presidency.
The figure was initially put at $2.1 billion when a former National Security Adviser, retired Colonal Sambo Dasuki, was arrested.
Tucker was said to have received part of the money in order to negotiate a peace deal with Boko Haram during the Jonathan administration.