article_snippet: Marcus Johnson Jr visited O'Fallon Park with Marcus Johnson Jr parents, four siblings, and other friends and family members while recovering from heart surgery one week earlier.
article_snippet: Marcus Johnson Jr had a post-operation appointment the day of the shooting.
article_snippet: mother Quiana Johnson said that Marcus, who was in kindergarten, had suffered from a heart ailment since birth.
article_snippet: Marcus suffered from a heart ailment and had surgery the week before Marcus was shot.
article_snippet: Marcus had been at a post-operation appointment prior to going to the park.
article_snippet: Johnson said Marcus, Johnson youngest son, was diagnosed with a heart ailment as an infant.
highlights_snippet: Marcus Johnson Jr had heart surgery a week before the incident and a post-operation appointment the day of the shooting .
  