A senior executive at United Airlines is the subject of a police missing person investigation.
The whereabouts of Jake Cefolia, senior vice president of worldwide sales, has been unknown since 6 August.
He was reported missing on 8 August.
An Elmhurst Police Department search has been focused at the Waterfall Glen Forest Preserve, in the suburbs of Chicago.
He is a resident of Elmhurst and often went running in the forest preserve.
Police said Cefolia’s abandoned vehicle was found there.
More than 100 people and police dogs have searched the forest preserve without luck so far.
Cefolia has been at United since 2007.
A statement released by the airline said: "We’re concerned about his well-being and have been in touch with Jake’s family over the last couple of days to offer them our support. At the request of the family, we won’t be releasing any additional details at this time."
Written by Ray Montgomery, US editor
