Mr Mangione's cases involve different charges arising from the same course of conduct.If Mr Mangione pleads guilty, his lawyers could then ask the judge in the state case to throw out those charges on double-jeopardy grounds State prosecutors argue their case is distinct and double jeopardy should not apply.Mr Mangione's federal charges allege that he travelled across state lines by bus to stalk and kill Mr Thompson and that he used means such as a mobile phone, the internet, interstate highways and staying at a hostel that serves out-of-state customers while planning and carrying out the attack. The state charges pertain to the killing itself, as well as firearms offences.Mr Mangione's decision to plead guilty comes after a series of setbacks for his defence.In January, US District Judge Margaret Garnett took the death penalty off the table but ruled that prosecutors could use items collected from Mr Mangione's backpack during his arrest as evidence against him.They included a 3D-printed pistol that investigators said matched the one used to kill Mr Thompson and a notebook in which authorities said Mr Mangione described his intent to kill an insurance executive.In June, Mr Mangione's lawyers said they would pursue a psychiatric defence in the state case but then reversed course a day later