More than 100 officers and agents and helicopters have joined the intensified search for Travis Decker, suspected of killing his three daughters in Washington state.

Authorities have closed a wide swath of popular campgrounds and backpacking areas along the Pacific Crest Trail in Washington as they search for a former Army soldier wanted in the deaths of his three young daughters.

Travis Decker is a former member of the military who has enough wilderness survival skills to live in the woods on his own for weeks or months, the authorities said.