Lee Harvey Oswald met with a KGB agent just two months before the assassination of President John F. Kennedy, according to newly unsealed confidential documents stemming from JFK’s murder.

The CIA memos, part of a trove of nearly 1,500 documents released Wednesday by the National Archives and Records Administration, also disclose that an anonymous tipster warned US embassy officials in Australia a year earlier that Kennedy would be assassinated by the Soviet Union for a $100,000 bounty.

But the tip was never passed on to the CIA.