DALLAS (AP) _ A gorilla that was shot to death by police after breaking out of its enclosure at the Dallas Zoo in March escaped by leaping over a 12-foot-wide trench and a wall that separates animals from visitors, officials said Tuesday.

Jabari, a 340-pound western lowland gorilla, went on a 40-minute rampage March 18, snatching up a toddler with his teeth and injuring three other people.

The gorilla enclosure is constructed so that animals are roughly at visitors' eye level, but they are separated from visitors by a 14-foot wall and the trench.

Zoo investigators believe the gorilla probably got a running start and sailed over the trench and the wall, clearing an electrical wire atop the wall that is supposed to give a mild shock.

``This is strictly a gorilla doing something that no one ever anticipated that a gorilla could do,'' zoo Director Rich Buickerood said as the zoo released the results of its investigation and reopened part of the exhibit.

The wire was not broken and had no hair on it, suggesting the gorilla was airborne when it cleared the wall, zoo spokeswoman Ellen Villeneuve said.

Young gorillas such as 13-year-old Jabari sometimes engage in athletic displays for other animals, Buickerood said.

``We know gorillas are typically not leapers,'' he said. ``But we do know that particularly these younger guys like to do these display runs. And they charge around the habitat showing off. And we think that's exactly what Jabari did.''

The zoo investigation found no human errors that might have led to the gorilla's escape, such as doors left open.

The zoo is raising the walls to 15 feet.