It is unpleasant news for US President Donald Trump: His longtime confidant Roger Stone was arrested on Friday in Florida. Trump's former campaigner is accused of obstructing investigations, according to special investigator Robert Mueller's office. Stone is said to have made several false statements. He also allegedly tried to influence a witness.

An FBI team around Mueller is investigating whether there were collusion of the Trump camp with representatives Russia in the 2016 presidential election campaign. Trump scourges the Russia investigation regularly as a "witch hunt". Stone is already one of several suspects in Trump's direct environment.

Stone worked for Trump in 2015 - preparing for the 2016 presidential campaign. He continued to be in close contact with him afterward, as a kind of informal adviser.

Wrong information before congress

Specifically, it is about the hacker attack on e-mail accounts of the Democrats during the election campaign 2016, for the US intelligence to blame Russia. The attack had stolen emails from Democratic presidential candidate Hillary Clinton, later published by the Wikileaks revelation platform.

Mueller's team accuses Stone of misrepresenting to the US Congress what he knew about the hacker attack and with whom he communicated about it. In addition, he is said to have harassed another witness to make false statements in the matter.

The Mueller bureau also said that in 2016, in consultation with representatives of Trump's campaign team - unspecified - Stone discussed the issue of whether and how further incriminating evidence against Clinton could be published.

"Will not plead guilty"

Stone defends himself. He was falsely accused, he said. "I'm not pleading guilty," says the 66-year-old in front of current television cameras, after he was released on payment of a bail from custody. He also announced that he would not testify against Trump under any circumstances.

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Sarah Huckabee Sanders

The White House spokeswoman, Sarah Sanders, struggled to reject any connection of the allegations with Trump. "The allegations against Roger Stone have nothing to do with the president," Sanders told television channel CNN. "The president has done nothing wrong." There were no collusion with Russia.

Stones name fell in connection with the Russia affair again and again. He was once an associate of President Richard Nixon and looks back on a long career as a dazzling but controversial lobbyist and policy advisor.

"Will never testify against Trump"

In December, Trump quoted Tweet Stone saying, "I'll never testify against Trump." Trump wrote that Stone did not let a runaway investigator make lies about him. Trump added, "Good to know that some people still have guts!"

The Russia investigation is increasingly putting Trump in distress. Already half a dozen people from his immediate environment have been accused in the investigations and some have already been convicted - including Trump's former campaign manager Paul Manafort and Trump's former lawyer and longtime confidant Michael Cohen.