Nigeria's anti-corruption commission has a tough job - the country is ranked the second most corrupt in the world according to Transparency International.
The commission to fight corruption was one of the bodies set up by President Olusegun Obasanjo soon after he came into office in 1999.
Nigeria's poverty fuels its corruption
But in all that time, its work has led to the conviction of just one public official.
Now the commission has sprung a surprise by launching an investigation into the activities of the country's most influential politicians.
Parliament has responded to this by challenging the activities of the anti-corruption commission itself.
Is this an act of self preservation by the politicians or just a coincidence of timing? Senator Mamman Ali argues strongly for the latter.
I was offered a parcel with three million Naira [about $20,000]
"It's a total coincidence," he said.
"We have certain issues as individuals against the anti-corruption commission, but in the conduct of our legislative duties we don't have to take personal issues that far."
But for Nigerians, this latest challenge to the work of the anti-corruption commission only strengthens the belief that the politicians have something to hide.
"If the law says they should be prosecuted, they should be prosecuted, because nobody is above the law. I don't think anybody should be above the law," said one.
Accusations of corruption are not just from ordinary individuals or the media, but from within the senate itself.
The best way to fight corruption is through leadership by example
Senator Saidu Mohammed Dansadau
Recently, in a remarkable piece of parliamentary theatre, Senator Mamman Ali walked to the front of the chamber and handed over a large bag full of cash. He said it had been given to him in order to influence his vote in parliament.
"I was confronted by some people in my house: 'Take this, then you forget'," he said.
"I was offered a parcel with three million Naira [about $20,000].
"I was confronted by them. I had never known them, so I said, 'OK, thank you.' I collected it and immediately moved to the senate floor."
It is the source of that money, alleged to have been handed out to many other senators in return for voting against a motion to impeach President Obasanjo, which the anti-corruption commission is attempting to investigate.
President Obasanjo set up the commission when he came to power
Chairman, Justice Mustapha Akambi, believes it will be an important test of the commission's powers.
"I want to believe that in the final analysis, this is a test case of whether any anti-corruption in this country will work in accordance with the law that established it," he said.
But whilst the anti-corruption commission can investigate, cases are almost invariably delayed or thrown out by the courts.
Just one minor official convicted in three years is not an impressive record.
Senator Saidu Mohammed Dansadau, of the newly-formed senate committee of corrupt practices, is certainly not impressed with that record.
"The best way to fight corruption is through leadership by example," he said.
"I believe rather than reducing, corruption is getting higher and higher. What we require is the political will by the president and the leadership to fight corruption."
The senator is saying no more than what all Nigerians know at heart - it does no good setting up committees and identifying corrupt practices if Nigeria's leaders fail to condemn loudly and at every opportunity, financial misconduct at the highest level.