A missing 11-year-old girl with Down syndrome has been found dead in a pond after wandering away from her school.

Jennifer Caballero, known as Jenny to her friends and family, was last seen at 1 p.m. Monday walking away from Rogers Middle School in Riverview.

"It's a terribly sad situation," said Hillsborough County Sheriff David Gee during a press conference Monday night.

Gee said the middle school staff was keeping a close eye on her because of unusual behavior.

"In class today they had paid special attention to her because she had kind of stood behind the bleachers earlier today and they had notified us that they were concerned that she may try to walk out,” he said.

Jenny somehow managed to walk away from her PE class, even though the class of 20 students had six teacher’s aides.

"I think that is a question that obviously we have to get answers too and that's exactly what we're going to be doing,” said Hillsborough County Schools Superintendent MaryEllen Elia. "Obviously, this is something that we feel terrible over as a school district. I as a superintendent and the staff here we cannot do anything to change what occurred but we have to do a full investigation so we can all understand this."

Gee said the pond is located a couple hundred yards away from the school and is surrounded by a four-foot chain link fence.

"We think she was physically capable (to get over the fence)," he said.

According to the sheriff's office, divers searching the pond found the child in water approximately 12 feet deep, and approximately 20 feet from the shore line. The pond has zero visibility.

“Our investigation is centered around this pond, finding out how this occurred today, how the events transpired,” Gee said.

School officials say they are working with law enforcement to try and figure out what happened.

"We have to get all of those pieces of information about the day that she was having, any events that might've triggered her being upset and trying to wander away,” Elia said. “Those things are all unanswered questions at that time but clearly we have a lot of work to do to find out exactly what happened today."

The area by the school is heavily-wooded. The sheriff's office searched the area for several hours with at least 75 deputies, K-9 units and aviation units.

Divers will be out Tuesday morning to continue their search.

“We just want to make sure there’s nothing else in the water, so we’ll be looking for anything that shouldn’t be there," Gee said.

Gee got choked up when asked about breaking the news to the parents.

"But they are doing as well as they can right now at the moment,” Gee said.  “Like I said, (it's a) terribly sad situation that we find ourselves in."

The focus now turns from the search to the investigation, including the events that led up to Jenny’s disappearance and how she was able to, as officials say, walk out of the building.
 
"We do not know how long she was not in direct supervision," said Gee, adding that it was too early in the investigation to answer such questions.

As for right now, the Sheriff, as well as so many others, not only at the school, but the community, as well, are trying to comprehend the tragic events.

"I can't even begin to tell you how said it is," Gee said.

The family was too upset to talk about the tragedy.

Elia said she couldn’t remember the last time a student died on a school campus.