This documentary by Al Jazeera America, uploaded to YouTube in Oct., 2014, tells the story of the Israeli attack upon the USS Liberty. The unprovoked attack by Israel, the closest ally of the United States, killed or wounded approximately two-thirds of the crew and nearly sunk the ship, which was later scrapped as a result of the severe damage it had sustained.
The USS Liberty was a U.S. communications interception ship (spy ship) that was attacked on 8-Jun-1967 by the Israeli air force and navy in international waters off the coast of Egypt during the 6 Day War between Israel and Egypt. Machine guns, rockets, napalm and torpedoes were all brought to bare during the attack. Apparently not satisfied with the nearly complete destruction of the ship, the Israelis also machine-gun the life boats to prevent the sailors from escaping the fate that Israel had planned for them.
Researchers have known for a long time that there was no question that the attack was deliberate, however it seems that the motive may not have been clear. My brief research into the incident seemed to indicate that the motive was to blame the attack on Egypt, thus prompting the U.S. to provide military support to Israel (a classic false-flag operation). The film implies a very different hypothesis however.