The Senate Homeland Security and Governmental Affairs Committee announced late Friday that it will investigate the events surrounding the death of four Americans in Libya, including the U.S. ambassador.

Chairman Joe Lieberman (I-Conn.) and ranking member Susan Collins (R-Maine) made the announcement in a joint statement.

“We intend to examine the circumstances before, during, and after the attack, including threat awareness, U.S. security needs for diplomatic personnel in Benghazi and Libya, and communications among the intelligence community, the State Department, the Defense Department, and the White House,” Lieberman and Collins said.

An early story line suggested the attack on the U.S. consulate in Benghazi on Sept. 11 of this year that took the lives of four Americans, including Ambassador Chris Stevens, was caused by a riot over an anti-Muslim video, but that has fallen apart. And various administration officials have given different accounts about what happened.

Since the Sept. 11, however, it has become clear that there were requests to bolster security in the country that went unmet before the consulate was attacked. Most officials now acknowledge it was a planned terrorist attack on the consulate.

The inquiry by Lieberman and Collins should differ considerably in tone from an investigation being conducted by the House Oversight and Government Reform Committee under Chairman Darrell Issa (R-Calif.). That investigation has been politically charged, with Democrats pushing back on Wednesday.

“We intend to examine how well the interagency processes worked, including whether all the relevant agencies had timely access to necessary intelligence information. And we want to fully understand why the Administration’s initial public assessments of this attack were subsequently proven inaccurate,” they said.

Asked about the security situation in Benghazi during Thursday’s vice presidential debate, Vice President Joseph Biden signaled parts of the administration were not aware of the requests for additional security measures.

“We weren’t told they wanted more security there. We did not know they wanted more security again,” Biden said.

White House Press Secretary Jay Carney sought to clarify Friday that Biden was speaking specifically about the White House, not the government at-large.

Collins has been skeptical of the security situation at the consulate in Benghazi from the beginning, telling Roll Call about her concerns just days after the attack.

“My overwhelming concern is that I don’t understand why the consulate was not better guarded, given the attacks that were aimed at the British ambassador in June, the bomb that exploded outside the consulate – also in June,” Collins said Sept. 14.