The New York police commissioner also said investigators matched Luigi Mangione's fingerprints with those found on items near the scene where the UnitedHealthcare CEO was fatally shot last week.
Wray told employees at an FBI town hall that he is resigning next month to "avoid dragging the Bureau deeper into the fray." President-elect Donald Trump has already made a new pick for FBI director.
There are big unknowns about what might have led a suspect arrested for the shooting of the UnitedHealthCare CEO to allegedly commit the crime. Many experts are looking at the suspect's digital trail.
With the arrest of Luigi Mangione, police have apprehended and charged a suspect in the killing of UnitedHealthcare CEO Brian Thompson, though many questions remain unanswered.
Luigi Mangione, 26, was arrested and charged with murder on Monday. He was found at a McDonald's in Pennsylvania, but is expected to be extradited to New York.
A Florida prosecutor says he will seek to vacate as many as 2,600 convictions of people who bought crack cocaine made by the Broward County Sheriff's Office for sting operations between 1988 and 1990.
Mangione was arraigned on firearms and forgery charges in Pennsylvania after his arrest Monday evening, and is expected to face charges in New York as well.
Trump's pick to head the FBI has parlayed his time serving in various national security roles in the first Trump administration to building a brand promoting pro-Trump conspiracy theories.