NILES, Ill. — A heavy police presence was seen in a Cook County forest preserve Tuesday.

According to Forest Preserves of Cook County Police, law enforcement searched a forest preserve near the 6700 block of North Milwaukee Ave in Niles, along the North Branch Trail near the Chicago River.

Forest Preserve officials said the heavy police presence in the area was a part of a missing person’s investigation in which law enforcement searched around the river and surrounding preserves for most of Tuesday afternoon and evening.

While Forest Preserves police began the investigation, the Chicago Police Department has taken over as the leading investigative agency and will provide updates moving forward.

No other information is available at this time.

Stay with WGN as this story develops.