Angry social media users flooded the hospital's switchboard and social media accounts after a cruel post went viral on social media.
The post identifies the user as Brittany Jill Michael, a nurse at Mass General. The post features a meme that shows gun violence victim Cannon Hinnant.
The meme reads: "Free Bike! I got this bike from my neighbor who don't need it no more. Has some red stains on it."
Cannon, 5, was shot in the head at point blank range while riding his bicycle in his own yard in Wilson, North Carolina on Aug. 9.
Police arrested 25-year-old ex-convict Darius Sessoms a day later at a private residence in Goldsboro NC. He was charged with first-degree murder and ordered held without bond.
The Facebook post fired up conservatives who called the hospital demanding to know if the Facebook user was a nurse on staff there.
Mass General updated the hospital's Twitter account to confirm the Facebook user is not a an employee, and they are working with Facebook officials to identify the user.
The Facebook account has since been deleted.
"This individual does not work at Mass General. We recommend that you report the profile to Facebook, as we have done. We are working with Facebook officials and the appropriate authorities to identify the person or people who are responsible for this hurtful message."