By Joe Holden

PHILADELPHIA (CBS) — Police are investigating after a human skull and bones were found at the Awbury Arboretum in the East Germantown section of Philadelphia on Monday. Investigators say the groundskeeper found the remains inside a sack that was partially buried behind Cope House on Awbury Road, just before 9 a.m.

Crime scene investigators emerged with the human remains around 1 p.m. Monday. What happened and how the remains came to be there are shrouded in mystery.

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It’s unclear if police have a sense of how long the remains were there, but workers at the Awbury Arboretum believe the remains couldn’t have been there long.

One thing that’s clear, neighbors living a stone’s throw away from the burial site are perplexed.

(credit: CBS3)

“That’s definitely a freak accident or an anomaly. We’ve never had that problem,” neighbor Darin Williams said. “The street is very quiet. I moved up here so my kids could play. They play, nobody bothers them. It’s always been a great time living up here, been up here six years.”

“This is the worst scenario I’ve heard,” Joseph Skinner said. “A body killed and decayed, that’s terrible.”

A groundskeeper made the discovery around 8:45 a.m. on Monday.

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Police say a skull and a partially decomposed body were located in a sack that was placed just below the soil.

The arboretum closes at dusk and is not gated, and neighbors living nearby where the discovery was made are uneasy.

“That’s really concerning. I didn’t think that would happen,” Skinner said. “But it’s an open area, like a park. Nobody is really monitoring it at a night, so we as neighbors should monitor it ourselves.”

Some neighbors say they were on the property on Sunday for an event and saw nothing out of the ordinary.

“I have never heard of anything regarding the arboretum like this. Nothing,” neighbor Pauline Taylor said. “I’m taken aback, floored. I don’t know what else to say.”

The investigation remains in the early stages. The next step will come after a thorough analysis by the medical examiner.

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“We get a lot of events back there — weddings and that,” Skinner said. “For something like that to happen, it’s rural back there. We have deer and stuff like that. I’m surprised to hear about that.”