US President Donald Trump looks on as he hands out diplomas to Coast Guard cadets at the commencement ceremony at the US Coast Guard Academy, May 17, 2017 in New London, Connecticut. This is President Trump's second commencement address since taking office and comes amid controversy after his firing of FBI Director James Comey.
Sources: Trump to hire outside attorney
01:59 - Source: CNN
CNN  — 

President Donald Trump is expected to hire attorney Marc Kasowitz to represent him on matters related to the inquiry into his campaign’s alleged ties to Russia, according to a senior administration official and a person close to Trump.

Kasowitz has represented Trump on a “wide range of litigation matters for over 15 years,” according to the biography posted on the website for his firm, Kasowitz Benson Torres LLP.

Kasowitz has not responded to requests for comment.

The President’s legal defense has become increasingly complicated as more details have surfaced in the investigations into Russia’s meddling in the 2016 election. The decision to retain Kasowitz comes as there are multiple congressional probes into the Trump campaign’s contact with Russians, as well as an FBI investigation.

White House lawyers have even been researching impeachment procedures in order to prepare for such a possibility, CNN reported last week. Close advisers to Trump, including lawyer Michael Cohen, visited the White House last week to discuss the potential need to hire a personal legal team to represent the President.

Some Democrats have said they would be willing to pursue politically charged impeachment proceedings after the revelation that former FBI Director James Comey wrote in a memo that Trump had asked Comey to end his investigation into former national security adviser Michael Flynn.

But so far, most lawmakers – including top Democrats – have been reluctant to discuss impeachment in public.

CNN’s Saba Hamedy and Evan Perez contributed to this report.