Book about time travel to the Eruption of Vesuvius era

Question

I read this amazing book about time travel, where people seems to randomly travel back in time where:

• Main protagonists appear in or near Pompeii with memory loss.
• The book ends with the Eruption of Mount Vesuvius, and all returning to the present era.
• They want to seek revenge of the organization and the people making the experiments that turned their lives into chaos.

I don't remember the name nor author. I'm almost sure the writer was a female. Any help would do.

Answer 1

I think it is Linda Evans's The Far Edge of Darkness

ALL ROADS LEAD TO ROME

Sibyl Johnson—a graduate student In classical archeology, just this side of her Ph.D., when an anachronism at her dig in Italy causes her career to take a sudden lurch—and suddenly she's a slave in the very society she was studying!

Charlie Flynn—a Miami cop, deep undercover on a Mafia sting operation stumbled onto something he shouldn't have seen, end now he's scheduled for a hit—in the Roman forum. Lagan McKee—once a commando, now a bum, he got caught in a Florida thunderstorm and suddenly he was in Alaska—five years after the storm struck. Now he's slated for a fatal visit to the dark side of Classical Rome.

Three people, all castaways in time, all victims of the same evil hand—all out for vengeance, on the Far Edge of Darkness.

This book was to have a sequel, but according to Ms Evans she ran into serious medical issues and the sequel remains unwritten. I do remember it as a good book, myself.

I initially thought this might be the book "Time Scout" by Robert Asprin and Linda Evans. Another in the series deals with Jack the Ripper, so it might be dark enough. It does involve the woman time traveller to Rome being raped.