The husband and father of two of the apparent victims did not attend, saying he was just emotionally drained. CBS News Correspondent Vince Gonzales reports.
Out of sheer frustration, friends and family of the missing women marched in downtown Modesto, Calif. They say they hope to bring more attention to this mysterious case, which has investigators stumped.
"This mysterious disappearance is a clear evidence of how vulnerable a mother and two girls can be in this society," said one speaker at the rally.
Another said, "We hold hope that someone will come forward soon and lead us to them."
Carole Sund; her daughter, Julie, and a family friend, Silvina Pelosso, vanished almost one month ago, while on a sightseeing trip to Yosemite National Park.
At first, it was thought they had been in a car accident in the snow-covered park, but weeks of fruitless searching and the discovery of Carole Sund's wallet more than 80 miles away in Modesto, has turned investigators away from the accident theory.
Now the FBI says the women were most likely victims of a violent crime. But they have little evidence and no official suspects. However, they are taking a hard look at Billy Joe Strange, an ex-con who worked at the lodge where the women were last seen.
Strange was jailed last week for a parole violation, and the FBI impounded his car.
People who knew Strange say he was violent. "Not only did he beat me up, but he beat up my sister," said Kathi Strange, Billy Joe Strange's former sister-in-law and his ex-girlfriend.
She added, "The FBI, when they came to my house, said that they were uncomfortable with the interview they had with him because they felt he was not entirely forthcoming."
At the rally, the families were joined by the relatives of other missing persons, some of whom waited for years of word of their loved ones.
Everyone called for a rapid solution to the mystery of the three missing women.