"Angelina was very proactive in asking for bribes," Alkostar said. "Her role was very significant."
Sondakh has denied any wrongdoing. She was a lawmaker from 2004 until being arrested in 2012 and had campaigned against corruption.
The cases which underline Indonesia's challenge in changing its graft-ridden image have threatened the credibility of the party's founder, President Susilo Bambang Yudhoyono, whose 2009 campaign for re-election presented him as the "Mr. Clean" of Indonesian politics.
Hundreds of people have been arrested for alleged corruption since Yudhoyono took office, though critics note high-ranking officials have largely been left alone.
According to advocacy group Transparency International's corruption index, Indonesia ranks 118th out of 176 countries polled, down from 100th out of 183 the year before.