Zaccaglini was last seen leaving her boyfriend's apartment in McCloud, California at approximately 10:00 p.m. on June 4, 1997. She was walking to her family's residence on Minnesota Avenue near Shasta Avenue, which is one or two blocks from her boyfriend's home. Zaccaglini never arrived and has not been seen again.

Zaccaglini was initially believed to have run away. Her parents recently divorced at the time she vanished and she had just broken up with her boyfriend; she was upset because he and his family were moving away. Authorities suspected that other factors were involved in her case as the investigation progressed. Zaccaglini had not argued with her family and she had left the majority of her personal belongings at her residence, including her clothing, purse, money, hairbrush, overnight bag, and bass guitar. Zaccaglini was a cheerleader and an aspiring model at the time she vanished. Her family maintains that she would never leave her home voluntarily, as such actions were uncharacteristic of her.

Authorities learned that Ed Henline Sr. and his wife, Deborah, may have been the last people to see Zaccaglini before she vanished. The Henlines owned a home on east Minnesota Avenue in McCloud, which was near Zaccaglini's last known location. Another young woman, Karen Knechtel Mero, also vanished from that locale in February 1997, four months prior to Zaccaglini's disappearance. Mero once lived in the Henlines' residence and they were reportedly the last people to see her as well. The Henlines were questioned in both cases and their home was searched by law enforcement, but the couple has never been connected to either disappearance. Authorities maintain that the Henlines have not been ruled out as suspects in the cases, however. They were arrested on drug charges in 1999, two years after Zaccaglini disappeared.

Another possible suspect in both Zaccaglini and Mero's cases is Wesley Howard Shermantine Jr. A photo of Shermantine is posted below this case summary. Shermantine was convicted in 2001 of four murders in California, including the presumed deaths of Chevelle Wheeler in 1985 and Cynthia Vanderheiden in 1998. It is not known if Shermantine is involved in either Zaccaglini or Mero's disappearances and the investigations are ongoing.

Zaccaglini's mother stated the police were prejudiced against her and initially did not investigate her daughter's disappearance as thoroughly as they should have. Foul play is suspected in Zaccaglini's case. Her disappearance remains unsolved.

Above: Shermatine, circa 2001