A man who had been arrested in 2010 for making online threats against President Obama has been linked to a spate of robberies, the killing of a police officer and the wounding of another.

Authorities say during a single day last week, Mario Edward Garnett attempted a bank robbery in Atlanta, committed a robbery in Mississippi, fatally shot a police officer in that state and wounded another officer.

Garnett, 40, was shot and killed by a detective Saturday as he tried to rob a bank in Phoenix.

Secret Service spokesman Max Millien told the Associated Press Sunday that Garnett had been living in Oklahoma City when he was arrested in 2010.

Garnett threatened to “blow [Obama's] brains out” in a post on the official White House website. 

In 2011, he pleaded guilty to threatening the president and was sentenced to eight months in federal prison. He was ordered to receive mental health treatment once he was released.