Lindsey Graham of South Carolina, John McCain of Arizona, Kelly Ayotte of New Hampshire and Ron Johnson of Wisconsin said in the letter they have failed to get answers from U.S. agencies about the Sept. 11 attack on the U.S. Consulate, Fox News reported Wednesday.
Ambassador Christopher Stevens and three other U.S. nationals were killed in the attack.
The four senators said the public has a right to know what Obama knew about the attack and when he knew it, and what was done to protect the consulate and ambassador ahead of time.
"Your failure to answer these important questions will only add to the growing perception among many of our constituents that your administration has undertaken a concerted effort to misrepresent the facts and stonewall Congress and the American people," the senators said.
Notable deaths of 2014 [PHOTOS]