PITTSBURGH — The Pittsburgh zoo plans to close the African painted dog exhibit where a boy was mauled to death last fall and move the 10 wild canines once kept there to other zoos, the zoo’s president announced Wednesday, and a prosecutor suggested the investigation into the death was all but over.

Pittsburgh Zoo & PPG Aquarium President Dr. Barbara Baker said the zoo staff and surrounding community still “need time to heal” from the death of 2-year-old Maddox Derkosh, who was killed Nov. 4 when he fell from the railing of an observation platform overlooking the exhibit and attacked by several dogs.

The boy’s mother had placed him on the rail to give him a better look, when he unexpectedly lunged forward and fell. He is the only visitor to die at the 115-year-old zoo.

Allegheny County District Attorney Stephen Zappala Jr. expects to close his investigation into the boy’s death, he also announced Wednesday, barring unforeseen findings in a separate U.S. Department of Agriculture probe.

The boy bled to death and Zappala determined relatively quickly that his mother, Elizabeth Derkosh, 34, shouldn’t be prosecuted for his death, which Zappala called a “tragic accident.”