Russia investigation latest: Lawyer arrested for lying to Robert Mueller probe over Trump campaign links

Dutch national Alex van der Zwaan has been sentenced to 30 days in prison, two months of supervised release, and will be forced to pay $20,000 in fines for lying to special counsel Robert Mueller's team about his contacts with Trump campaign officials.

Van der Zwaan, 33, is the son-in-law of a Russian oligarch and had entered a guilty plea in February for lying to Mr Mueller's investigators about contacts he had with former Trump campaign chairman Paul Manafort and his deputy Rick Gates. Those interactions occurred while Van der Zwaan was working in Ukraine.

He does not have any known ties to the Trump campaign specifically, but sentencing discussions filed in court showed that Van der Swaan and Mr Gates had discussions with a former Russian intelligence officer during the final months of the 2016 presidential campaign.

The specifics of those investigations were not disclosed by Mr Mueller in the filings, and the intelligence officer was only referred to as "Person A" on the documents. A source familiar with those fillings told ABC News that the unnamed individual is Konstantin Kilimnik, who is a longtime business associate of both Mr Manafort and Mr Gates.

Mr Kilimnik has denied the allegations that he is the individual.

Mr Manafort and Mr Kilimnik have worked together as recently as last year, when the two worked on an opinion article designed to burnish Mr Manafort's image in Ukraine. That effort was a violation of a court-imposed gag order that had been placed on Mr Manafort – he has been charged with relation to the special counsel investigation as well – and a judge admonished the former Trump campaign official for the document.

Mr Manafaort has been accused of crimes including conspiracy, money laundering, and tax evasion, and is awaiting trial for those charges. He has pleaded not guilty, and his lawyers have sought to have the charges dismissed by arguing they are not directly related to the 2016 campaign.

Mr Gates pleaded guilty to the charges in order to received reduced charges, and is reportedly cooperating with Mr Mueller's investigation.

It is not clear exactly how Van der Zwaan will help Mr Mueller's probe, and federal Prosecutor Andrew Weissmann has submitted paperwork asking for limited public access to records relating to the case.

“Van der Zwaan is in an unusual position of having information related to the Office's investigation that is not widely known – including information that he knows first-hand due to his role in the conduct the Office is investigating,” Mr Weissman wrote.

“Requests filed by someone with non-public information could, themselves, suggest to third parties investigative facts that are otherwise not widely known.”

Before his sentencing, Van der Zwaan could have faced up to five years for the crime. Federal guidelines generally call for zero to six months in prison for his charges.