Paul Manafort’s legal headaches just intensified.

The former Trump campaign chairman has been indicted on additional new charges. He is being charged with obstruction of justice and conspiracy to obstruct justice. Manafort’s business partner Konstantin Kilimnik has also been indicted.

Manafort has already been a target of special counsel Robert S. Mueller. He is under house arrest and awaiting trial after having been charged with bank fraud, conspiracy to launder money, and other crimes. He plead not guilty.

Earlier in the week, Mueller’s team accused Manafort of witness tampering and asked a judge to consider ending the former Trump advisor’s house arrest.

Mueller’s probe into possible collusion between the Russian government and members of the Trump campaign during the 2016 presidential election has already resulted in charges being brought against 20 people and three companies. There are four former campaign associates among the indicted – Michael Flynn, Richard Gates, George Papadopoulos and Manafort.

Manafort’s initial indictment stemmed from work that he did before he joined the Trump campaign. It involved claims that he acted as an unregistered agent of the government of Ukraine and its Russian-backed leader, Victor Yanukovych, who was president from 2010 to 2014. The indictment claims that Manafort, working with his associate Gates, generated tens of millions of dollars in income from his work and hid it from U.S. authorities.

Gates reached a plea deal in February and agreed to cooperate with the special counsel investigation.

The latest indictment adds new charges related to accusations that Manafort engaged in witness tampering.

It claims that between Feb. 23 and April of this year, Manafort and Kilimnik tried to persuade witnesses with “intent to influence, delay, and prevent the testimony of any person in an official proceeding.” The witnesses were former business associates who worked on an effort to promote Yanukovych among European leaders and get them to make statements in support.

The new indictment is here.

Ted Johnson contributed to this report.