President Donald Trump's son-in-law and senior adviser, Jared Kushner, is under FBI scrutiny as part of the Russia investigation, according to US media. Reports say investigators believe he has relevant information, but he is not necessarily suspected of a crime. The FBI is looking into potential Russian meddling in the 2016 election and links with Trump's campaign. The president denies any collusion. Kushner's lawyer said his client would co-operate with any inquiry.