( NewsNation) — Montana Gov. Greg Gianforte and Attorney General Austin Knudsen will hold a news conference Tuesday as a search for the suspect in a deadly bar shooting moves into its sixth day. Michael Paul Brown, 45, a U.S. Army veteran, is accused of killing four people at the Owl Bar in Anaconda, Montana, on Friday.

Stymied by treacherous terrain and untamed wilderness, authorities are struggling to find an Army veteran suspected of killing four people at a Montana bar. But the difficult landscape isn’t the only challenge.

Many manhunts end quickly, but the man accused of killing four people in rural Montana appears to have disappeared into the kind of wilderness that helps elude pursuers.