An investigation is now underway into the cause of a massive fire at Point Pelee National Park.
Leamington Deputy Fire Chief Mike Bradt says initially it was believed to have been caused by natural causes.
But he says recent information has come to light that has led the park to investigate further.
Bradt says for the fire department's purposes, the cause is being listed as "undetermined."
Leamington fire crews were called just after 8pm on Wednesday to the fire which destroyed about 300 acres of the marsh.