Early details on security at White House Correspondents' Dinner prior to shooting 05:59

The White House Correspondents' Dinner shooting suspect wrote a "manifesto" which stated he wanted to specifically target administration officials, law enforcement and White House officials told CBS News.

Authorities also found anti-Trump and anti-Christian rhetoric on the suspect's social media accounts, the official said.

Cole Allen, 31, sent some of his writings to members of his family before the attempted attack on Saturday, and one of them alerted police about the writings. The writings sent to family members apparently did not specifically mention the White House Correspondents Dinner.

Another family member who was interviewed by investigators after the attack said Allen made radical statements and that he constantly referenced a plan to do "something" to fix the issues with today's world.

Family members told investigators Allen would regularly go to the shooting range to train with his guns. He legally owned two guns, one of which was used in the shooting at the Washington Hilton Hotel, law enforcement officials told CBS News.

Allen's family members also said he was part of a group called "The Wide Awakes" and attended a "No Kings" protest in California.