Artist and political activist Yoko Ono tweeted a photo of John Lennon's bloody glasses on Wednesday, on the day of what would have been their 44th wedding anniversary, reported by NBCNews.com.
"Over 1,057,000 people have been killed by guns in the USA since John Lennon was shot and killed on 8 December 1980," her Tweet read.
Lennon was shot by Mark David Chapman outside the New York City Dakota apartment building where he and Ono lived. A retweet by the account associated with President Obama forwarded it to his more than 28 million followers.
Obama's Twitter account is run by Organizing for Action, the political group formed from the president's re-election campaign organization.
"The death of a loved one is a hollowing experience," Ono tweeted. "After 33 years our son Sean and I still miss him."
One of Organizing for Action's first major initiatives is promoting Obama's gun control proposals, which were unveiled in the aftermath of December's deadly school massacre in Connecticut.
"Together, let's bring back America, the green land of peace," Ono tweeted.
Ono's photo of Lennon's glasses- has been retweeted more than 11,000 times since it was posted on Wednesday.
A proposed assault weapons ban was stripped from a bill headed to the Senate floor, much to the disappointment of many gun control advocates.