Police allege that Monroe had taken the child with him to a drug deal where he intended on using counterfeit money in the hope that the presence of a young child would deter the drug dealers from acting violently if he was caught out.
It's understood that he was sitting in a car with his son and girlfriend when the gunman opened fire.
Head of the District Attorney's Homicide Office, Anthony Voci said 'it is our belief that he intentionally had his child with him when he was making such types of purchases, with the idea, or the belief that if someone saw that he had a child in the car that they would not fire upon him'.
'A human shield is the term that I would probably use,' he added.
The alleged gunman has also been arrested and charged with attempted murder.