In the proposed order attached to the filing, Mangione's attorneys also asked that the Metropolitan Detention Center permit him to wear the civilian clothing while being transported to court for the Aug. 11 hearing.
"Mr. Mangione ... does not have civilian clothes to wear for the court appearance," the filing states. "We therefore request – without objection from Judge Carro or the government – that this Court order the Bureau of Prisons and the MDC to accept" the clothing.
The filing says Carro and prosecutors do not oppose the request, a routine procedural step for defendants in federal custody appearing in another court system.
The latest filing comes as Mangione's defense team has continued an aggressive pretrial campaign surrounding the closely watched case, challenging restrictions on media access, arguing courtroom coverage limits violate constitutional rights and seeking to livestream portions of the proceedings.
Prosecutors with the Manhattan District Attorney's Office have pushed back, accusing the defense of making false and misleading claims about the court's media policies in an effort to influence public opinion.
Mangione is accused of fatally shooting UnitedHealthcare CEO Brian Thompson outside a Manhattan hotel on Dec. 4, 2024, before fleeing the scene.
Authorities arrested him days later at a McDonald's in Altoona, Pennsylvania, after an employee recognized him and alerted police.
Mangione has pleaded not guilty to state and federal charges stemming from Thompson's killing.
Fox News Digital has reached out to Mangione’s attorney, Karen Friedman Agnifilo, for comment.