Newly obtained federal court documents show that Cole Tomas Allen pre-scheduled a series of emails, including a resignation to a former employer and a lengthy manifesto-style attachment, for delivery at about 8:30 p.m. on April 25 — the same window prosecutors say he opened fire at the Washington Hilton as guests prepared for the White House Correspondents' Dinner.

A copy of one email to a former employer contained what appeared to be a routine exit and an apology for the "unprofessionality" of his actions. Allen wrote, "I'll include the full text as an attachment," and added, "Consider me to be submitting my resignation effective immediately (if it matters.)," the filing shows.

Prosecutors say Allen also sent messages to family and friends with a manifesto-style attachment titled "Apology and Explanation," in which he both apologized and sought to justify his plan.

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As per 13Wham in the manifesto, Allen wrote, "I apologize to my colleagues and students for saying I had a personal emergency," acknowledging he had misled people to conceal his intentions.

He also addressed bystanders, writing, "I apologize to all of the people I traveled next to" and "all the other non-targeted people at the hotel," and added, "I apologize to everyone who was abused and/or murdered before this... and to all who may still suffer after," the documents state.

Prosecutors say the manifesto included what Allen described as "rules of engagement," identifying targets and indicating he would push through "most everyone" in his path if necessary, a detail they call a chilling admission of the danger he posed.

The timeline of the messages and their content was cited in court filings as evidence that the alleged attack was "premeditated, violent, and calculated to cause death," Radar Online reported.

According to authorities, Secret Service agents intercepted Allen before he reached the ballroom where President Donald Trump and other officials were gathered. The documents say Allen allegedly sprinted through a security checkpoint armed with a shotgun and fired toward a stairwell leading to the event. Trump and first lady Melania Trump were evacuated quickly when gunfire erupted, the filings say.

If convicted on the charges he faces in U.S. District Court in Washington, Allen could be sentenced to life in prison, prosecutors told the court, as cited by the outlet.

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