In East Africa, Rwanda has some of the severest laws and policies against corruption, including tapping the phones of suspects, imposing severe fines and publicising the names of people convicted of the crime and their families.

Prosecutors say that the measures have been helpful in gathering strong evidence that would otherwise be difficult or illegal to obtain.

Indeed, prosecutors relied on such evidence to win 289 corruption-related cases between June 2017 and June 2018, up from 121 in 2016. Some of the cases required phone call records as evidence in courtrooms.

Whereas a total of 76 cases were lost for lack of evidence, prosecutors appealed some of them.

“The conviction rate is 79 per cent,” said the spokesperson of the National Public Prosecution Authority Faustin Nkusi. “The prosecution has done a lot in gathering evidence to ensure that we do not lose cases, and the national laws have been helpful.”

Those convicted face long jail terms and are ordered to return the full amounts of the embezzled funds, plus a fine three times what was stolen.

Companies caught in corruption are ordered to pay up to seven times the value of the contracts they were awarded illegally.

The phone-tapping law has however proved controversial, with concerns raised over its potential misuse by authorities to invade the privacy of individuals.

Proponents say that it is probably one of the best tools through which corruption can be effectively tackled among high-ranking government officials.

“Corruption is difficult to prove. Phone tapping provides strong evidence. Phones are tapped only after a warrant is issued,” said the chairperson of Transparency International Rwanda, Marie Immaculée Ingabire.

According to the law passed in 2012 and amended mid this year, a phone interception warrant is issued by a national prosecutor designated by the Minister of Justice — and only intelligence services and the Office of the Ombudsman can conduct it. The warrant can be issued verbally, but the written warrant must be completed within 24 hours, after which it is presumed illegal.

Ms Ingabire said that equal emphasis must be placed on the private sector, where phone tapping could unearth massive corruption.

“We have noted a high level of corruption, bribery and tax evasion in co-operatives, markets and civil society, and there must be specific effort by government to curb this,” she said.

Over the past couple of months, a number of district mayors and leaders resigned citing "personal reasons,” but some were eventually arrested on suspicion of corruption and abuse of office.

However, the Auditor General’s Report 2017 shows that various agencies have unsupported debtors and creditors, while their budgets have significant balances that are omitted from financial statements.

A total of 16 accounts, valued at Rwf638 million ($0.73 million) were omitted from financial statements of six institutions, including the Rwanda Social Security Board, University of Rwanda, Rwanda Energy Group and four district hospitals.

According to Transparency International, more than 1.5 million Rwandans encountered bribes in 2016 — while local government agencies and police received almost two-thirds of the total Rwf35.5 billion ($41 million) of bribes paid out throughout the year.

Rwanda is ranked the third least corrupt country in Africa, according to the 2017 Corruption Perception Index by Transparency International.