Daniel Dale Lambert was last seen on his 43rd birthday, September 8, 2015, at his home on Forest Leaf Parkway in Wildwood, Missouri. Family reported he left personal belongings behind and did not return; the case was filed with the St. Louis County Police Department and entered into national missing-person databases.

A week after his disappearance his maroon and red 1997 Ford Ranger pickup was found abandoned at a campsite in a section of the Mark Twain National Forest in Washington County. Extensive searches of the rugged surrounding terrain by law enforcement and volunteers failed to locate him. A suicide note and a map of the 1.5 million-acre national forest were found at his residence, introducing the possibility he intended to harm himself but providing no definitive explanation.

The investigation remains open and there have been no significant breakthroughs that explain what happened after he left home. If anyone knew Daniel, his movements that day, or saw his pickup in the Mark Twain National Forest, please share what was observed.