UPDATE: Investigators Questioning 'Persons of Interest' in Bomb Threat

Update, 12:07 p.m.: Independence Grove Forest Preserve could remain closed until Friday as officials continue their investigation into bomb threat received by the Lake County Forest Preserves.

Julie Kenney, public information representative for the United States Postal Inspection Service, said investigators are "questioning persons of interest" in relation to the threat, which was received by mail in a letter.

"That's why the postal inspectors are involved," Kenney said of the investigation, which is being led by the Postal Inspection Service.

So far, investigators haven't found anything suspicious at Independence Grove, Kenney said.

"This is an ongoing investigation," she said.

------------------

Original story: Libertyville's Independence Grove is closed to the public as federal officials investigate a bomb threat, the Lake County Forest Preserves District announced Wednesday morning.

The bomb threat was directed to a specific target at Independence Grove Forest Preserve, according to a press release. All events and activities have been suspended until further notice pending a complete investigation of the threat.

Federal authorities were notified immediately and a full investigation is underway. The U.S. Postal Investigation Service is leading the investigation, with assistance from the Bureau of Alcohol, Tobacco, Firearms and Explosives. Lake County Forest Preserve Ranger Police are working in cooperation with these federal agencies and other local authorities.

Lake County Forest Preserve officials are taking every necessary precaution to secure the site and to protect the public until the investigation is complete. Independence Grove will reopen when authorities deem the area safe for public use.