Las Vegas (KTNV) Maria Herrera's ex-boyfriend left her threatening phone calls. But her family didn't realize that those threats were real, until it was too late.

Maria is just one of several women killed in the Valley this month, by an ex-boyfriend or spouse. But deadly domestic abuse is not a recent problem. According to a new study by the Violence Policy Center, 28 women were murdered in Nevada in 2007.

That makes Nevada the fifth deadliest state in the nation.

"In the last 5 years, we've been in the top 5," says Maria Outcalt, an advocate with Safe Nest. "That lets you know that we have a lot of issues not being dealt with."

Outcalt would know. In 2004, her sister Anna was killed by a boyfriend she was trying to leave.

So when Maria looks at homicide statistics, she says, "That's a real person, that's not just a number. It's a real person."

But as alarming as the cases that turn to murder are, domestic violence advocates say what's even more alarming are the cases not being reported.

"The real problem is every day, women are being abused physically, psychologically, going to hospitals. And no one is reporting any of those things."

That's why Outcalt hopes the new study, and the recent crimes, are a wake up call. She says more domestic violence prevention programs are needed in this state.

"I think what we're doing now is help after the fact. Well, you can't help after they've passed away."

Stay tuned to Action News.