The gunman accused of opening fire at the White House Correspondents’ Association dinner this past weekend is expected to appear in court Thursday for a detention hearing, as his attorneys push for his release.

Cole Tomas Allen, a 31-year-old teacher and engineer from California, was charged Monday with attempting to assassinate the president and related crimes after he allegedly began shooting outside the packed Washington Hilton ballroom, where President Donald Trump and other White House officials had gathered with journalists for the annual dinner.

Allen was arrested after a U.S. Secret Service Officer fired at him multiple times. A criminal complaint states that Allen fell to the ground and sustained minor injuries, but was not struck by gunfire.

In a court filing Wednesday in support of Allen’s pre-trial release, his public defenders argued that he has no past criminal history and was "gainfully employed as a tutor" in California. The attorneys said that he "has support from family and friends" who would make sure he did not violate the conditions of his release.

"As previously stated, Mr. Allen’s history and characteristics counsel in favor of release in this case," the public defenders wrote, calling him a "loved and respected teacher and colleague who has always demonstrated kindness, empathy and compassion and never violence."

Assistant U.S. Attorney Jocelyn Ballantine argued for Allen to be held in pre-trial detention. She alleged that he traveled to Washington with a pump-action shotgun, a semi-automatic pistol, three knives and "other dangerous paraphernalia."

A criminal complaint alleged that Allen approached a security checkpoint on the terrace level of the hotel around 8:40 p.m. Saturday. Allen had been a guest at the hotel.

He then ran through a magnetometer with a long gun, and as he did so, secret service personnel heard "a loud gunshot," according to the complaint. Federal investigators said a U.S. Secret Service Officer, who was wearing a ballistic vest, was shot once in the chest. That officer fired "multiple times" at Allen, who was not shot.

Trump and top members of his Cabinet and Congress were evacuated from the room. The officer who was shot was taken to the hospital for treatment and later released.

Just moments before the attack, Allen sent his family members a note apologizing and criticizing Trump without mentioning the President by name, according to a transcript of some of his writings provided to NBC News by a senior administration official. He also wrote that "administration officials (not including Mr. Patel)" were "targets."

The charge of attempting to assassinate the president of the United States carries a sentence of up to life in prison if convicted.

Allen was also charged with transportation of a firearm and ammunition through interstate commerce with intent to commit a felony, which carries a sentence of up to 10 years if convicted.

The third count he was charged with was discharge of a firearm during a crime of violence, which can carry a sentence of an additional term of a mandatory minimum of 10 years in prison.