Lambton OPP say a missing 71-year-old man has been found, deceased.
Police said Allan was last seen around 5 a.m. Sunday in the area of Highway 402 near the Nauvoo Road exit.
The eastbound highway at Forest Road and westbound lanes at Nauvoo Road were closed for part of the day as part of the investigation.
The roadway fully reopened just after 4 p.m.
Further details, including Allan's last name, were not immediately available.
If you have any information, contact Ontario Provincial Police at 1-888-310-1122 or Crime Stoppers at 1-800-222-8477 (TIPS) where you may be eligible for a cash reward of up to $2,000.