Deep in the archives of the Los Angeles Police Department is a room they call the tunnel.

Filled with files that were once active investigations, now there is dead as the victims.

And those stay dead unless a cold case investigator like Detective Richard Binkston can somehow bring them back to life.

We're the last chance homicide detectives because once we've looked at it, if we can't solve it, then nobody else is going to look at it.

But where to begin?

Just in the near 50 years between 1960 and our visit, 9,000 unsolved homicides landed in that dustbin of justice.

How do you solve 9,000 cold cases?

You know what, you can't.

But if you can just solve one, one unsolved case that nobody else could solve, just bring answers to one family that didn't have answers before.

In 2002, Binkston was assigned to a 30-year-old triple homicide.

In 1972, Lois Petri, a recently-without-woman in her 40s, killed on the bed of Ramangolo.

Two years later, Catherine Medina, a middle-aged laundry worker, turned up dead in the park.

A month after that, the nude body of 53-year-old Anna Feltsch dumped on the side of a road.

It appeared the victim shared the same killer who had raped and strangled them all, leaving no evidence behind.

I don't know if we knew we had a shot at cracking it, but I enjoy putting the pieces back together.

Pieces? What pieces? Well, no one knew it yet, of course.

But there was a piece, a clue for this unsolved puzzle, in Pittsburgh, Pennsylvania.

Her name? Jeannie Loudenberg.

Around the time of the murders back in 1975, Jeannie was a college student who met a guy who lived in California.

They decided to move in together, so she flew out to the coast, San Luis Obispo, to find an apartment.

Her bow was out of town, so his stepfather, a man named Adolf, picked her up at the airport.

They hit it off.

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