Former Chilean dictator Augusto Pinochet's wife and son were arrested on charges they helped commit tax fraud.

Lucia Hiriart Pinochet is being held at a military hospital in Santiago and her son Marco Antonio Pinochet at a local jail, Alejandro Espinoza, a court spokesman, said yesterday by telephone. They may be freed on bail of 2 million pesos ($3,685) each as soon as Friday, Espinoza said. Pinochet, 89, visited his wife at the hospital, Radio Agricultura said.

"This is another step to enable us to untie the hidden, illegal plot that Pinochet organized around him to hide his fortune, which from our point of view was obtained unlawfully," Carmen Hertz, a human rights lawyer, said in an interview.

Chilean courts are investigating the origin of at least $15 million that a U.S. Senate subcommittee said Pinochet's family stashed in accounts overseas. Among them were accounts at District-based Riggs Bank (recently bought by PNC Financial Services Group Inc.) that totaled as much as $10 million at one point. The case may lead to charges of tax fraud against Pinochet, said Alfonso Insunza, a human rights lawyer who requested courts investigate the accounts. An appeals court in June stripped Pinochet of immunity afforded him as former president in order to broaden the investigation. His lawyers appealed the June ruling, Insunza said.

The Pinochet family's lawyer, Pablo Rodriguez, said today that the charges against Lucia Hiriart Pinochet are "persecutory" and "unjust."

Her properties are separate from those of her husband and she had almost no involvement in the affairs under investigation, he said in comments broadcast on television. Luis Pacull, a lawyer for Marco Antonio Pinochet, said his client is innocent, according to state-run National Television.

Marco Antonio Pinochet is escorted by a jail guard after his arrest yesterday in Santiago, Chile. He and his mother are expected to be freed on bail.Lucia Pinochet is in a hospital.