A memorial is growing for a 13-year-old girl whose life was cut short this week when her body was found in a Fairfield park.

Flowers, stuffed animals and balloons were left for the middle school student, whose naked body was discovered at Allan Witt Park Friday morning by a citizen, who flagged down an officer around 6:45 a.m.

Eric May said he was walking through the Fairfield park when he saw the girl's body.

"I thought to myself, that looks like a mannequin, didn't look like a human body," May said. "The closer I got, the more real she looked. As I got up to her I thought, 'Oh my God, that's a human being, or was a human being.'"

May later gave investigators a DNA sample.

"Rule me out and go after the people that did this thing," May told KTVU Saturday.

The girl was a foster child who attended Green Valley Middle School, although she lived with a guardian in Suisun City.

"It's scary," said Barraness Thompson, a mother of the victim's classmate. "It's very scary."

Thompson's son was friends with the victim.

"He has two classes with her and he rides the bus with her," Thompson said.

And now he's devastated, she said.

Word that the girl was a student at Green Valley shocked people at a nearby park.

"You don't hear about stuff like that in Fairfield, so it's kind of weird, especially something like that on that kind of level," said 17-year-old Daniel Barnett.

Police have yet to release the girl's name or her cause of death.

"We've had probably 30-plus investigators here all day yesterday and all day this morning, and probably through the weekend," said Fairfield police Sergeant Robert Lenke.

Police said they have some good leads, but that they need more information from the public.