Nigerians have been shocked and bemused after huge piles of cash have been unearthed in various parts of the country in recent months. Journalist and writer Adaobi Tricia Nwaubani looks at what is going on.
In February, $9.2m and £750,000 were discovered by Nigeria's anti-corruption agency, the EFCC, in a property belonging to Andrew Yakubu, a former director of the national oil company, NNPC.
In March, large sacks containing bundles of "crispy" banknotes worth a total of $155,000 (£130,000) were found in Kaduna airport.
In April, a stash containing $43.4m, £27,800 and 23.2m naira were recovered from a Lagos apartment with its owner yet to be identified.
And these are just the tip of the iceberg.
EFCC head Ibrahim Magu was quoted in the local media as saying that the total amount recovered by the agency in the past few months was about $53m, £120m and €547m, on top of hundreds of millions of Nigerian naira.
He credited this to the whistle-blower policy put in place by the government in December 2016.
A particularly juicy sentence stands out from the five-page policy document made available on the ministry of finance website:
"A whistle-blower responsible for providing the government with information that directly leads to the voluntary return of stolen or concealed funds or assets may be entitled to anywhere between 2.5-5% of amount recovered."
There is a special page for submitting tip-offs.
Within three months Finance Minister Kemi Adeosun disclosed that they had received 2,351 tips, sent in through phone calls, text messages and emails.
Naturally, the policy also promises to protect the identity of all whistle-blowers.
Such huge sums of cash as those discovered could not have walked into the residences on their own.
The typical Nigerian wealthy man or woman, indisposed to manual labour, would have had to enlist the services of their extended family, minions or hangers-on, to transport the cash.
In the past, whistle-blowers or not, it may have been difficult to find any large amounts of cash lying around in Nigeria.
The stashes would have been cooling off in banks, or en route to various foreign destinations.
But, in 2012, the Central Bank of Nigeria (CBN), under Sanusi Lamido Sanusi, now the Emir of Kano, introduced a "cashless policy".
This placed limits on the amount of cash-based transfers, encouraging electronic transactions instead.
As the CBN notes in the "Cash-less Nigeria" section of its website: "High cash usage enables corruption, leakages and money laundering, amongst other cash-related fraudulent activities."
Imagine the predicament of the serial looters, bribe givers and takers, accustomed to handling incredible amounts of cash.
Recent reports, for example, allege that in 2011 a whopping $466m was withdrawn in cash - raw notes and bundles - to pay a few Nigerian government officials to facilitate Shell Petroleum's acquisition of a lucrative oilfield. Shell said it did not believe its employees acted illegally.
The CBN's cashless policy would have made it hard for subsequent bribe-takers to deposit such huge sums in banks.
Again, the extended family, minions and hangers-on can come to the rescue.
People could open different bank accounts in the names of their siblings, aunts and uncles, father, nephew, spouses, in-laws, house girls, cooks, drivers and so on.
The heaps of cash can be broken into smaller batches and deposited in these various accounts.
Those in whose names the accounts are opened might not have any knowledge of or control over the transactions.
This short-circuiting of the cashless policy seemed to be working fine, until President Muhammadu Buhari came to power and introduced yet another policy: The Bank Verification Number (BVN) policy.
Every bank customer in Nigeria was required to have their biometric details captured and linked to a unique number that could be verified across every account and transaction they made in every bank.
The first step to getting a BVN was to turn up at the bank in person.
As of November 2016, the Nigerian parliament was set to discuss the billions of local and international currency reportedly abandoned in bank accounts as a result of the BVN policy.
Apparently, owners of dubious accounts are afraid to step forward and claim their riches.
Banks in Nigeria are definitely no longer the best hiding place for unexplained funds.
The $9.2m found in Mr Yakubu's residence was discovered in a fireproof safe.
He has sued the EFCC for violating his fundamental human rights, insisting that the money was his - a "gift from unnamed persons".
After much speculation as to its ownership, the $43.4m found in a Lagos apartment was finally claimed by the Nigerian Intelligence Agency (NIA), whose director, Ayo Oke, stated that the money was released by the previous government to help with the agency's "special services".
Mr Buhari has suspended the director from his position and ordered a two-week probe into the origin of the funds.
Two years into his tenure, President Buhari's war on corruption is finally producing tangible results - cash - even if there have been no high-profile convictions yet.