(NewsNation) — As the manhunt for Travis Decker moves into his fourth day, the intensity in apprehending him has intensified.

Authorities believe Decker may be traveling along the Pacific Crest Trail. Park officials closed a wide portion of hiking trails in the Lake Chelan National Recreation Area within the Cascade Range late Thursday as the search continued.

Earlier Thursday, officials closed the popular network of hiking trails known as the "Enchantments." The Chelan County Sheriff's Office has also advised residents in the county to lock their doors and remain vigilant.

In addition, digital search warrants have been executed on Decker's electronics.

Travis Decker accused of killing his daughters

Decker is suspected of killing his three daughters in Chelan County. The sisters, ages

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