The incident happened on South Road and Wood Street in Jamaica around 10 p.m.
It began when 10-year old Jacob Rodriguez ran out of the house, screaming that his mother was being beaten up by an ex-boyfriend.
Officer Joseph Koch, who specializes in domestic violence cases and had just left a Father's Day barbecue, heard the boy and rushed into the house with his firearm drawn.
He struggled with the suspect, 40-year-old Jose Bernazard, and three shots were fired.
Koch was shot one time in the left hand, the bullet breaking several bones, while Bernazard was hit three times, in the neck, hand and abdomen.
Both were taken to Jamaica Hospital, where they are listed in stable condition.
The initial victim of the domestic violence assault, Chrissy Rodriguez, was also taken to Jamaica Hospital in stable condition, where she was treated for a 7-inch laceration to her head.
Jacob Rodriguez is most grateful to Officer Koch, who heard the boy's frantic cries for help.
"I met him before, he's a pretty cool guy. He also saved my life," said Jacob.
The officer left the party, then ran down the sidewalk and vaulted the 6-foot fence.
"He's bolting down the block, over the gate like Captain America! I grabbed my cellphone," said neighbor Troy Jordan.
As Koch entered the house with his gun drawn, police officials say he was suddenly attacked by Bernazard, who is charged with beating Chrissy Rodriguez.
Rodriguez reportedly had an order of protection against Bernazard.
Troy Jordan believes it could have been much worse.
"It could have been a double homicide," said Jordan. "No doubt that the perpetrator would have popped both of them and then jumped out the window."
Instead, Jacob and his family are offering their thanks to Koch.
"Very grateful. I would never know how to be thankful. And he wasn't even on duty. He was an angel sent from heaven," they say.