Former National Assembly Speaker Park Hee-tae and former presidential aide Kim Hyo-jae have been indicted for their alleged involvement in a political bribery scandal.

Park was indicted for allegedly bribing a fellow ruling party politician when Park was running for election as chairman of the Grand National Party, now called the Saenuri Party, in 2008, a Yonhap News Agency report said.

Kim allegedly was a key player in the scandal while he was helping Park work to win the chairmanship. Envelopes of money were allegedly distributed to Grand National Party politicians, including one member, Koh Seung-duk, the Yonhap report said.

In 2010, Park left his job as chairman of the party to become speaker of the National Assembly.

Park has denied the bribery allegations since Koh raised them in early January.

Koh said Park's aide delivered to his office envelopes containing around $2,670 in cash and Park's name card right before the July party convention in 2008. Koh said he returned the money to Park's aide, the Yonhap report said.

The indictments come after nearly two months investigation by police and Kim's resignation earlier this month. Kim was the senior political affairs secretary to President Lee Myung-bak.

Lee accepted Kim's resignation after it became known police wanted to interview him in connection with the bribery allegations, Yonhap reported at the time.

Park could be sentenced to three years in prison if found guilty but prosecutors have admitted difficulties in building a case.

"We were striving to find out which lawmakers other than Koh took bribes (from Park) but couldn't do it because of their reluctance to come out," a prosecution official said. "Investigations into bank accounts were also fruitless because the bribes were delivered in cash."

The indictment of Park marks the first official charges ever brought against a parliamentary speaker, Yonhap said.

Also, the indictment of Kim, a former section editor with Chosun Ilbo newspaper, is another in a line of journalists who have moved into political advisory roles only to become victims of scandals, an opinion piece in the independent newspaper Hankyoreh said earlier this month.

"Reporters who cozied up to powerful politicians are going down with them," said senior Hankyoreh staff writer Kim Do-hyung. "The very press figures who should be cleanest of all are leading the way in illegalities and corruption."

Park and Kim deny the charges and aren't in detention.