This is the puzzle the Economic and Financial Crimes Commission (EFCC) is trying to resolve.
The EFCC found the cash on Monday night, packed in sacks.
A man believed to be the owner ran away before EFCC operatives could question him.
The cash was discovered by EFCC Zonal Office in Kaduna in five large black 150kg sacks during routine baggage screening at the airport.
A top source in the commission said: “Upon careful scrutiny of the sacks, it was discovered that they contained fresh crispy naira notes of N200 denomination in 200 bundles totaling N40million and N50 denomination in 180 bundles totaling N9million.
“The bundles were all sealed, purportedly emanating from the Nigerian Security and Minting Company (MSPMC) as seen in the label on the packs.
“The five sacks were sighted unattended and without tags containing fresh bulk items suspected to be money from the aroma perceived from the sacks.
“The owner of the money later showed up but could not state the exact money in the sacks or present any document authenticating the genesis of the monies.
“However, his inability to give any concrete explanation made him become uncomfortable and he disappeared before the arrival of EFCC operatives.”
Another source said the EFCC was working on clues that the fleeing suspect might be a courier for a syndicate.
“We will get to the root of this crime. There is a way we can collaborate with some agencies to trace the source of the N49million.
“We will also deploy forensic equipment and retrieve CCTV footage at the airport to identify the suspect,” the source said, pleading not to be named so as not to jeopardise the investigation.