Police spokesman Ruwan Gunasekara said the brother, former Economic Affairs Minister Basil Rajapaksa, is accused of financial irregularities in a poverty alleviation program run by his former ministry. Two other senior ministry officials were also arrested.Basil Rajapaksa had vast powers over the country's economy during his brother's presidency. He left for the United States, where he also has citizenship, after his brother's defeat in a January election.
He returned to Sri Lanka on Tuesday in response to a police summons. The police financial crimes unit questioned him for several hours Wednesday before arresting him.
Since the new government took office, the Bribery Commission and police have initiated investigations into alleged corruption during the previous administration.
Former President Mahinda Rajapaksa also has been summoned by the Bribery Commission to explain why he gave a ministerial position last year to an opposition leader who defected to support Rajapaksa's presidential re-election campaign. Rajapaksa's rivals say the ministerial position was a bribe.
Another brother, former Defense Secretary Gotabhaya Rajapaksa, has been asked to appear before the commission on Thursday.
Rajapaksa loyalists have protested the summoning of the brothers, saying it is an affront to leaders who ended the country's 26-year civil war.
The brothers are credited with leading the military campaign that defeated Tamil Tiger rebels and ended the civil war in 2009. The rebels were fighting for an independent state for the country's ethnic Tamil minority.
According to a conservative U.N. estimate, about 100,000 people were killed in the conflict. The actual toll is believed to be much higher.
Related story
Cabinet determines perks for former presidents, vice presidents...
