FREDERICK, Okla. (AP) — The Oklahoma State Bureau of Investigation says the death of a Lawton man whose body was found in Frederick is suspicious.

The OSBI says the body of 73-year-old Curtis Thompson was found Tuesday in a drainage ditch by an employee of the nearby Farmers Co-Op.

Investigators say Thompson was in Frederick to attend family and school reunions and was last seen Saturday night.

The body is being sent to the state medical examiner's office to determine the cause and manner of death.