FBI tries to track movements of Orlando gunman

The FBI is analyzing cellphone data to try to piece together the activities of 29-year-old Omar Mateen in the hours and days before Sunday's massacre at Pulse nightclub in Orlando. Agents are also interviewing people who had any dealings with him. Authorities are trying to determine what role Mateen's wife may have played.

"We are combing, not just this street, but everywhere the shooter may have been in the days before this event, and so we are collecting all digital video and electronic evidence that we can," said FBI spokesman Ron Hopper.

Agents said they have also been to other gay clubs in Orlando, like the Revere Club off International Drive, looking for information. The club's owner said that agents would be collecting surveillance footage in regards to Mateen.

"We have put out intelligence bulletins and made contact to those clubs to give them a heightened sense of awareness," said Hopper. He said investigators do not think Mateen was casing other gay clubs. "At this time there was nothing to suggest there was any other target other then Pulse nightclub."

A Senate committee is asking the FBI to turn over its files on the gunman. In a letter Wednesday to Attorney General Loretta Lynch, the Senate Committee on Homeland Security and Governmental Affairs asked the FBI to provide records related to two previously closed investigations concerning Mateen.

The committee also requested details of the placement and removal of Mateen from a terrorist watch list, any prior visits to the Pulse nightclub or Walt Disney World before the attack and his travel to Saudi Arabia.

In addition, the committee said it wanted information about Mateen's use of social media before and during the attack, and the FBI's communication with state and local law enforcement about Mateen's comments about terrorism prior to the attack.

The FBI urged anyone with any information about the gunman to contact the agency directly.