3-year-old found wandering streets of Newark after leaving house

A 3-year-old boy was found wandering the streets of Newark late Tuesday morning after slipping out of his home unnoticed, authorities said.
Police say they were called to a firehouse on Sanford Avenue where the child was dropped off by someone who found the boy wandering the streets. 
Authorities say the boy's 21-year-old sister showed up at the firehouse and explained that he left the home without her knowing. The boy was found about a half block from his home.
The child, who police say was unharmed and showed no signs of injury, was taken to a hospital as a precaution.