A US diplomatic cable released by Wikileaks over the weekend says North Korea has likely received 2-and-a-half million US dollars for weapons sold to Iran through the Seoul branch of Iran's Bank Mellat.
According to the cable, Iran's Hong Kong Electronics transferred the money to the bank in November 2007.
Hong Kong Electronics is a front for North Korea's Tanchon Commercial Bank which manages funds from its weapon exports.
A thorough investigation into the bank's financial activities that year did not find any weapons-related financial transactions, but the South Korean government has been watching its activities ever since.
The Seoul branch was suspended from October 11th to December 10th last year as part of international moves to sanction Iran for its nuclear weapons development.