Jared Loughner, the man accused of killing six people and wounding then-US Representative Gabrielle Giffords in 2011, is set to plead guilty in a Tucson court on Tuesday, a person familiar with the case said.

The source confirmed that the federal government believed Loughner was now competent to stand trial and will argue that in court on Tuesday. Loughner is willing to change his plea to guilty at the previously scheduled hearing, the source said.

Psychiatric experts who have examined Loughner were scheduled to testify in a mental competency hearing on Tuesday that he was competent to stand trial and understood the 49 charges against him, the Los Angeles Times reported earlier.