By James Harding GiahyueMONROVIA (Reuters) - A grand jury in Liberia on Wednesday indicted government officials, including the speaker of parliament and the head of the ruling party, along with London AIM-listed Sable Mining on charges including bribery.President Ellen Johnson Sirleaf ordered an inquiry into Sable's attempt to acquire an iron ore concession in northern Liberia after the watchdog group Global Witness made accusations of wrong-doing in a report earlier this month.A grand jury in the capital Monrovia accused the defendants of bribery among other crimes, according to the indictment seen by Reuters.The indictment alleged that the defendants conspired to use their positions to amend Liberia's public procurement and concessions law. It asserted that they succeeded in changing the law to give the Minister of Lands, Mines and Energy the power to declare a concession area as a non-bidding area.The indictment did not specify how Sable Mining allegedly benefited from the change to the law and Reuters was unable to independently determine if Sable actually did.In its report Global Witness claimed that the amendment was intended to allow the company to win the concession without a tender. In the end however, Sable Mining was not awarded the property, known as Wologizi.A spokeswoman for Sable said the company would not comment on the accusations made in the indictment, which cover a period including 2010 and 2011.Previously Sable said the Global Witness report appeared to be based on "unreliable" testimony from three former business partners.The indictment named as defendants Sable Mining, parliament speaker Alex Tyler, Varney Sherman, a senator and chairman of President Johnson Sirleaf's Unity Party, and Deputy Minister of Lands, Mines and Energy Ernest C.B. Jones, as well as Christopher Onanuga, a Liberian businessman.All four men were arrested in Liberia's capital Monrovia on Wednesday and were later released on bail.Tyler has rejected the Global Witness report, which, like the indictment, alleged that bribery had been used to facilitate Sable's attempted acquisition of the concession.He was not immediately reachable for comment. His office said he was not planning to comment on the indictment, which alleges he requested and received $75,000 to help amend Liberia's procurement and concession law.As he left court on Wednesday, Sherman told reporters he would not comment on the indictment. While he acknowledged in a May 13 news conference that his law firm had worked for Sable, he denied the Global Witness allegations of wrong-doing.Neither Jones, accused in the indictment of receiving $5,000 for providing the technical advice for the alteration of the procurement and concession law, nor Onanuga responded to text messages and telephone calls. The indictment did not give specific details of the allegations against Onanuga.(Additional reporting by Guy Faulconbridge in London; Writing by Joe Bavier; Editing by Toni Reinhold)Join the conversation about this story Click here to read full news..