The court presiding over Bo's case heard that property tycoon Xu Ming paid €2.3 million (HK$23.5 million) on Gu's behalf for a villa in France, set up several companies, and borrowed from a bank to evade taxes and conceal the couple's links to the property, but Gu retained firm control and de facto ownership of the villa.

According to Gu's testimony, Xu also paid 3.2 million yuan for luxury travel for Gu's son, Bo Guagua , from 2004 to 2012. Guagua's trip to Africa in August 2011 cost Xu more than US$100,000.

Only Gu, not Guagua, gave evidence, in an 11-minute video clip and written testimonies.

Legal experts said both Gu and Guagua were culpable and that Gu should be prosecuted for economic crimes as well as murder. She should also appear in court to answer the charges.

"Legally speaking, Gu should face additional charges other than murder given her involvement in those business dealings," said Si Weijiang , a Shanghai-based human rights lawyer.

Another lawyer, Li Heping , said it was possible for authorities to introduce new charges against a convicted criminal if new evidence came to light. "It is legally sound to reopen the case or launch a separate trial even after a criminal has been convicted," he said.

The court may impose a combined punishment for several offences after the new trial and in some cases the convicted person might receive a harsher sentence.

However, it is unlikely that Gu will be given a tougher penalty as she is already serving a suspended death sentence.

"It is theoretically possible for the court to impose a death sentence without suspension," Li said. "But it is very unlikely in Gu's case, unless the court is convinced that the economic crimes were more serious than murder."

An indictment against Bo Xilai issued last month said Gu's case would be handled separately.