Up next, a family vacation turns into a nightmare. That's when I've seen the body of a female lying face down in the water. And possible clues provide more questions than answers. Either it was an accident, someone caused her death, or she killed herself. Experts can't seem to agree on exactly what happened.

There is not one single eyewitness to anything.

There are no confessions.

There are no fingerprints.

Until groundbreaking science discovers the truth.

Method, opportunity, motive, and last person to see them alive.

Classic reasons for murder.

Music motive, and last person to see them alive. Classic reasons for murder.

Every year, the younger family spent their vacation on the western shore of Lake Michigan in a place called Watervale.

It's almost a sanctuary for them

to go somewhere else in the state

where they can just forget about

the rest of the world

and reconnect with themselves

and their families and their loved ones.

Florence worked as a bank loan officer.

Her husband, Mark, a mortgage broker, was also a well-known radio personality.

Mark Unger had a sports radio show and made him somewhat of a celebrity with a circle of friends.

Their vacation in 2003 was like most others.

The Ungers checked into their cabin, had dinner, and Mark spent

time with their two sons, while Florence was outside for some fresh air. Mark read a story to the

boys, sang a song, put them to bed, kiss them good night, and came back out to the deck,

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