A huge manhunt is underway for the killer of Cristen and Clinton Brink, who were murdered during a hike with their daughters on Saturday.

Police in Arkansas are searching for a suspect in the deaths of a couple who were attacked while on a wooded walking trail with their two young daughters.

Relatives of Clinton and Cristen Brink described them as "heroes" for protecting their daughters, both of whom were left unharmed in the attack.