Photos of Tammy soon appeared from New Jersey to Iowa, in toll booths and rest stops and on TV screens: Tammy's bright eyes, long blond hair, glasses, the sweet round face of a girl. Missing.
The Zywickis camped out in the Chicago home of the parents of one of Tammy's friends. Every day, they went to the police station in LaSalle to wait. Every day they woke up saying, "This will be the day."
But nine days passed, and still no Tammy. They headed home.
They were changing planes in Cincinnati when some official approached and escorted them into a small room. Over the phone, they were told that a body had been found, 500 miles away, near I-44 in Missouri.
Tammy. Her body, stabbed over and over, had been wrapped in a blanket sealed in duct tape.
All over the country, the name Tammy Zywicki became synonymous with danger. Danger to young women, to college students, to parents who helplessly released their children into the world.
"In the beginning, you take it a minute at a time," said JoAnn Zywicki. "Then you go from that to hours. Then all of a sudden one day you think, 'Gee, I haven't thought about her today,' and you know you're moving on."
It was Tuesday and the Zywickis were back in their car, heading home to Florida, talking by phone.
Last week, during the flurry of reports on the FBI's announcement that the investigation was still active, complete with a $50,000 reward, they hadn't wanted to talk about how they spent the 20th anniversary.
Now that it's over, they hope that talking will inspire someone who knows something to come forward.
Hank, a civil engineer, was 52 when Tammy died. JoAnn, who had worked as a part-time temp while raising her four children, was 50. After Tammy's death, she took the most rote job she could find, filing.
"I could just file away and not worry about it," she said.
But they worried. They anguished. They waited for a killer to be caught, watching as leads flared and faded, as the task force dedicated to Tammy disbanded. For years, until she stopped trying so hard, JoAnn dogged law enforcement agencies, frustrated especially by the Illinois State Police.
There had been reports of a man with a semi-trailer truck who stopped for Tammy along the highway. Was the killer a trucker? A serial killer masquerading as a good Samaritan?
Suspects' names came and went. One suspect trucker, an ex-con who the family thinks is the likeliest culprit, has died. The Zywickis fear that everyone who knows anything will vanish before the case is solved.
"Primarily," Hank Zywicki said Tuesday, "what I would like to know was, what made this — I'm going to use the word idiot for lack of a better word — stab her so many times? Tammy was never the kind of person to antagonize anybody."
As he sat in his car, somewhere in Maryland, his voice broke.
The Zywickis keep photos of Tammy in the house, but not too many. They keep her seashells and mementos of Garfield, the comic cat she loved. When they got Wi-Fi not long ago, they named their network after Tammy.
Even so, they try to keep their loss in its proper measure. They know that at some point all parents have to let their children head into the world alone. They take pleasure from the notes they get from the recipients of the Tammy Zywicki scholarship at Grinnell, given annually to a student who values family and believes in relaxation as well as study.
"One of the things that's very inspiring about the two of them is that they didn't get absorbed by it," said Todd Zywicki, their oldest son and a George Mason University law professor. "It didn't defeat them, didn't drive them apart, didn't cause them to blame each other or be so overwhelmed by grief that they couldn't function. If anything, it made them more appreciating, not taking for granted their kids and grandkids."
When the Zywickis arrived at the cemetery last Thursday, the sun was out, the air was warm and the grass was freshly cut.
The pink geraniums at Tammy's grave, tended by JoAnn's sister, who lives nearby, were in bloom. Garfield the cat, engraved on the headstone, looked happy.
"It was peaceful," JoAnn Zywicki said. "A perfect day all the way around."
Tammy would have liked it.