On the Edge of Tomorrow - Lyle D. Westbrook - Bog

When an old friend asks a washed-up telepathic archeologist, Nathan Masterson, and his gifted dog Duke, to help unlock the mysteries of a very unique cave system along the British Columbia coast, a series of events would unfold that would open a vast subterranean tunnel system. A system filled with many unbelievable creatures and an ancient alien race, whose leader reveals the true origins of mankind.
Then after returning home to northwest Montana, a local veterinarian, Patricia Smith, is attacked on Halloween. After Masterson and his family offer their protection they find out a Colombian drug-lord and tomb robber, Beltran Velasco is behind the attack and will stop at nothing to get his hands on the ancient
medallion she has.

After the FBI and CIA get involved, Masterson puts together a full exploration team and make their way to an ancient temple complex atop a mountain in northern Guatemala where Valasco's people have already zeroed in on. It is here the exploration team is sent on a quest through yet another underworld system, full of monsters, huge cities, and great adventures, far below Central and South America.
Meanwhile the FBI AND CIA uncover a plot to kill the president after investigating the secret society the Velasco's are involved with".