As many others all over the world, I follow the Steven Avery case. Can you explain to me this matter? According to an article on the internet, "a federal judge has overturned the 1st Degree Intentional Homicide conviction for Avery's nephew, a decision backed up by a three-judge panel in a federal appeals court". I thought that this case must be treated within the frame of the law of the state (in this case Wisconsin). As far as I know B. Obama refused to grant a pardon from this reason. So why is the federal judge involeved in this case right now?
The Steven Avery case is explained in detail at Wikipedia.
Federal courts can collaterally review state court convictions in a habeas corpus action to determine if the conviction was obtained through a violation of a person's federal constitutional rights that the state courts refused to remedy after the person aggrieved attempted to obtain a remedy in the state court system.
In his case, the federal court found in a habeas corpus action brought by Mr. Avery that his conviction was obtained in violation of his rights under the United States Constitution because his confession was coerced, even though the state court system had refused to reverse his conviction on this ground.
The President of the United States cannot pardon a state court conviction even though a federal court can review the validity of a state court conviction in a habeas corpus proceeding.
Federal courts also have jurisdiction over lawsuits for money damages brought for violations of someone's rights under the United States Constitution committed by a local government or brought against a government employee, as opposed to against a state government per se, and Mr. Avery also pursued a violation of civil rights action in federal court earlier on in the saga of his case.