WOODSTOCK, New Brunswick – An investigation into a small-plane crash on the New Brunswick-Maine border last year will take longer than expected.

The July 19 accident killed two Canadians.

The cargo plane was on its way to Montreal from Halifax, Nova Scotia, when it went down and exploded in a river valley, just outside Houlton, Maine.

Luke Schiada of the U.S. National Transportation Safety Board said he hoped to put out a preliminary report later this month.

But that’s been put off because another review of radar data and the plane’s engines is being conducted.

Schiada didn’t say why they want to take a second look at those pieces of evidence.

He could not say when his report will be issued.