The armed man who entered a Washington DC pizza restaurant and allegedly discharged his gun inside after reading conspiracy theories about the Clintons had earlier texted a friend about "possibly" sacrificing lives, according to investigators.

The arrest warrant for Edgar Maddison Welch states that he walked into the Comet Ping Pong restaurant on 11 December at around 3pm, carrying a loaded assault rifle and revolver. Those inside fled the building and Welch fired the rifle a number of times, though no one was injured.

According to the warrant, officers found Welch's phone in his car outside, along with another firearm. The phone showed that Welch had been watching YouTube videos about 'Pizzagate' — a baseless conspiracy theory spread by fake news sites that Comet Ping Pong was the centre of a high profile paedophile ring.

The phone also allegedly showed that two days before the incident, Welch had texted a friend asking whether he had any army friends nearby. When the friend replied that he did, Welch asked whether the army friend was "down for the cause".

The friend replied that it depended on the cause, according to court documents now made public. "Raiding a pedo ring," Welch replied, "possibly sacraficing [sic] lives of a few for the lives of many."

Welch went on to say that he wanted to defend children from the evil that he believed was being perpetrated: "One day it will be our families. The world is too afraid to act and I'm too stubborn not to".

On the phone was also a video Welch had allegedly taken of himself while driving to Washington, D.C. from his home in North Carolina.

Welch was formally charged on 13 December with interstate transportation of a firearm with intent to commit an offence.