(Adds former energy minister investigation)
ALGIERS, April 24 (Reuters) - Four brothers from the Kouninef family - tycoons close to Algeria's former president Abdelaziz Bouteflika - have been placed in temporary custody by a judge, private channel Ennahar TV reported on Wednesday.
The channel did not cite a source for its report.
The four were arrested together with Algeria's wealthiest businessman, Issad Rebrab, on Monday as part of an anti-graft investigation.
Reuters was unable to reach their legal representatives.
Algeria's supreme court has started investigating cases of alleged corruption relating to Chakib Khelil, energy minister from November 1999 to May 2010, the channel also said, citing the court.
The cases include capital movements and contracts signed by state energy firm Sonatrach with two foreign companies, Ennahar TV said.
Khelil could not be reached for comment.
Army chief of statf Lieutenant General Ahmed Gaid Salah has urged the judiciary to tackle corruption scandals including those linked to the energy sector.
He also said last week he expected members of the ruling elite to be prosecuted for graft.
Protesters have called during two months of mass public protests for the removal of the elite that has governed Algeria since independence from France in 1962, and the prosecution of people they see as corrupt.
Bouteflika resigned three weeks ago but protests have continued as the manly young demonstrators want sweeping changes.
An Algerian court has already summoned former prime minister Ahmed Ouyahia and current Finance Minister Mohamed Loukal, two close associates of Bouteflika, in an investigation into suspected misuse of public money, state TV said on Saturday.
Bouteflika has been replaced by Abdelkader Bensalah, head of the upper house of parliament, as interim president for 90 days until a presidential election is held on July 4.
Hundreds of thousands protested on Friday to demand the resignation of Bensalah and other top officials. (Reporting by Hamid Ould Ahmed in Algiers and Ahmed Tolba in Cairo, Editing by William Maclean and Toby Chopra)
Our Standards: The Thomson Reuters Trust Principles.