Story highlights Former White House press secretary was wounded in Reagan assassination attempt

He died earlier this week from what his family said were health issues

But a Virginia medical examiner ruled it a homicide, prompting authorities to reinvestigate

Gunman John Hinckley was found not guilty by reason of insanity

Former White House press secretary James Brady's death this week was directly related to wounds he sustained in the 1981 attempted assassination of President Ronald Reagan, and authorities are now investigating it as a homicide, police told CNN on Friday.

Brady was shot in the head and partly paralyzed, spending the rest of his life in a wheelchair and advocating against gun violence.

His family said in a statement that he died from health issues at 73. But a Virginia medical examiner has ruled the case a homicide, prompting a new investigation, Metropolitan Police spokeswoman Gwen Crump said.

Bill Miller, a spokesman for the U.S. attorney in Washington, said his office is reviewing the medical examiner's findings. He had no further comment.

Photos: Gun-control advocate James Brady Photos: Gun-control advocate James Brady James Brady, alongside his wife Sarah, speaks in 2011 about new legislation curbing gun violence. He was a former White House press secretary who became a prominent gun-control advocate after he was wounded in the 1981 attempt on President Ronald Reagan's life. He died in August at the age of 73. Hide Caption 1 of 10 Photos: Gun-control advocate James Brady Reagan introduces Brady as his press secretary on January 6, 1981, in Washington. Hide Caption 2 of 10 Photos: Gun-control advocate James Brady Police and Secret Service agents react during the Reagan assassination attempt, which took place March 30, 1981, after a conference outside the Hilton Hotel in Washington. Lying on the ground in front is wounded police officer Thomas Delahanty. Brady is behind him, also lying face down. Hide Caption 3 of 10 Photos: Gun-control advocate James Brady Brady is placed into an ambulance shortly after being shot. He suffered a head wound and was left partially paralyzed. Hide Caption 4 of 10 Photos: Gun-control advocate James Brady Maryland Attorney General Joseph Curran reaches to shake Brady's hand outside the U.S. Supreme Court in October 1981. After leaving the White House, Brady launched the Brady Campaign to Prevent Gun Violence, which pushes for stricter firearms laws. Hide Caption 5 of 10 Photos: Gun-control advocate James Brady Brady, with his left hand in a sling, chats with his son, Scott, in November 1981. Because of the shooting, Brady had to use a wheelchair for the rest of his life. Hide Caption 6 of 10 Photos: Gun-control advocate James Brady Brady is next to President Bill Clinton as Clinton signs the Brady Bill on November 30, 1993. The bill, which was fiercely fought over for years before Congress approved it, required background checks for gun purchases. Hide Caption 7 of 10 Photos: Gun-control advocate James Brady Brady gives a thumbs-up to Clinton at the White House on September 9, 1996. Brady was receiving the Presidential Medal of Freedom, the highest civilian award in the United States. Hide Caption 8 of 10 Photos: Gun-control advocate James Brady Clinton congratulates Brady in February 2000, when the White House press briefing room was named in his honor. Hide Caption 9 of 10 Photos: Gun-control advocate James Brady Brady visits the White House Briefing Room with his wife as White House Deputy Press Secretary Bill Burton, left, shows them around in June 2009. Hide Caption 10 of 10

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John Hinckley , the lone gunman who fired the shots that wounded Reagan, Brady, a police officer and a Secret Service agent outside a Washington hotel, was found not guilty by reason of insanity.

He has spent the ensuing years in a psychiatric hospital.

Hinckley was charged at the time with assault with intent to kill and assault with a dangerous weapon, and it's unclear if he will face any new counts.