Wikipedia on the RFK Assassination

Forty years later, here's the money quote:

Sirhan Sirhan was strongly anti-Zionist. A diary found during a search of Sirhan's home stated, "My determination to eliminate RFK is becoming more and more of an unshakable obsession. RFK must die. RFK must be killed. Robert F. Kennedy must be assassinated. .... Robert F. Kennedy must be assassinated before 5 June 1968." It has been suggested that the date of the assassination is significant, because it was the first anniversary of the first day of the Six Day War between Israel and its Arab neighbors. When Sirhan was booked by police, they found in his pocket a newspaper article that discussed Kennedy's support for Israel. At his trial, Sirhan testified that he began to hate Kennedy after learning of Kennedy's support for Israel.

RFK's Palestinian assassin, Sirhan Sirhan, has his own Wikipedia entry here.