Andrew Banda, a son of Zambia's ex-President Rupiah Banda and the deputy high commissioner to India, has been arrested in Lusaka for corruption.Mr Banda is accused of taking a bribe from an Italian road construction firm of over $30,000 (£20,000).
He denies corruption, saying the payment was made by Fratelli Locci as a commission to his logistics company.
His father stood down as president last year after losing presidential elections to Michael Sata in September.
President Sata has launched a anti-corruption drive since coming to power that has seen a number of former ministers investigated and some arrested.
The BBC's Mutuna Chanda in the capital, Lusaka, says Mr Sata's opponents feel he is targeting the former leader and his associates as a way of settling political scores.
'Proceeds of crime' Police said the businessman and diplomat was also arrested for failing to account for $70,000 in his personal bank account.
"Andrew Banda has been formally arrested and charged for corrupt practices and being in possession of property suspected to be proceeds of crime," Namukolo Kasumpa, a spokeswoman for Zambia's police criminal investigations department, told reporters.
Police say he took a 2% cut from all Fratelli Locci's road-building contracts, but Mr Banda said the money was paid for the services he provided in helping the company register in the country.
Andrew Banda is the eldest son of Rupiah Banda.
His younger brother, Henry, is also wanted by police on a different set of corruption allegations and an international arrest warrant has been issued after he failed to come forward for questioning.
Reacting to his son's arrest, Rupiah Banda said he had not been in touch with him for "a long time now so I am not really following what is happening," the AFP news agency reports.
"But the courts have many people's sons and daughters, everybody goes before the police, so let's not make this an issue," he told reporters.
Andrew Banda has been released on bail, his lawyer Sakwiba Sikota said