State Police say Arnold Milfort, 27, of Dorchester, sustained serious injuries yesterday when he climbed a fence and then fell 30 feet into a gorilla pen that had been refashioned to look like a lion's den for a movie.

State Police report: "A member of the production crew told State Police that Milfort gained access to the closed set by claiming falsely that he was a zoo employee. Witnesses reported that he tripped and fell into the den shortly before 3:45 p.m."

Initial reports that Milfort was a teenager were based on the fact he looked young; investigators were unable to talk to him as EMTs got him ready for transport to Boston Medical Center.

Milfort, who remains hospitalized with serious injuries, has not been charged at this point.

The zoo is being used as a set for the filming of a Kevin James movie about a zookeeper who talks to the animals to get dating tips.