By Jacqueline Thomsen and Blake Brittain

A U.S. federal appeals judge facing a competency investigation has been unable to complete simple tasks independently and threatened a staffer with arrest, according to witness reports included in an order from her court on Tuesday.

An investigative committee of the U.S. Federal Circuit Court of Appeals rejected a request by Judge Pauline Newman, 95, to transfer the probe to another circuit. It ordered her to undergo a neurological evaluation and neuropsychological testing, with a Friday deadline to say whether she will comply.

The Washington-based Federal Circuit said it will not comment on the order or other related documents it released on Tuesday.

Newman last week sued in district court to halt or transfer the investigation, alleging constitutional violations.

A lawyer for Newman, John Vecchione of the New Civil Liberties Alliance, declined to comment on the new allegations, saying people who have seen the judge recently can gauge the claims "on their own." He criticized the committee's decision to not transfer the investigation, raising concerns about whether Newman's colleagues can be impartial.

According to interviews with court staff cited in Tuesday's order, Newman has frequently claimed without evidence over the last year that her devices - including her email, phones and computer - are being hacked or bugged.

In another episode described in the order, Newman said she did not have to comply with a court rule at the instruction of the chief judge, referring to a judge who left the court 32 years ago and died in 2006.

Newman also threatened to have one of her court staffers arrested, the document states.

"Though it is difficult to say this, I believe Judge Newman is simply losing it mentally," one staffer told judicial investigators.

The Federal Circuit disclosed the probe last month, citing concerns about Newman's ability to handle cases and her refusal to cooperate with the investigation.

Federal judges are lifetime appointees and can only leave their courts through retirement, resignation, impeachment, or death.

Newman was appointed by President Ronald Reagan in 1984 to the patent law-focused Federal Circuit, which often hears major cases involving technology and pharmaceutical companies.

(Reporting by Jacqueline Thomsen and Blake Brittain; Editing by Christopher Cushing)