WASHINGTON ― Sen. Lisa Murkowski (R-Alaska) reintroduced legislation on Monday to help law enforcement respond to a horrifying and largely invisible crisis: Hundreds of Native American women are simply disappearing or being murdered.

There is next to no data available on what, exactly, is going on. At least 506 indigenous women and girls have gone missing or been killed in 71 U.S. cities, including more than 330 since 2010, according to a November report by Urban Indian Health Institute. Most cases have been in the last decade, though the oldest case dated to 1943. But that 506 is likely a gross undercount, per the institute, because of the limited or complete lack of data being collected by law enforcement agencies. A staggering 95 percent of these cases were never covered by the national media, and the circumstances surrounding many of these deaths and disappearances remain unknown.

The overall level of violence faced by Native women is equally appalling. A whopping84 percent of Native women experience violence in their lifetime, and in some tribal communities, Native women are murdered at10 times the national average.

Murkowski’s bill, called Savanna’s Act, is as much an attempt to put attention on the epidemic of missing and murdered indigenous women as it is to understand the severity of the situation.

“We don’t even know what we don’t know with this,” the Alaska senator said in an interview. “It is a challenge, at best, to try to understand the extent of the problem. And if you can’t understand the extent of the problem, it’s really hard to know how to properly resource it.”

Her bill would boost coordination and data collection among tribal, local, state and federal law enforcement in cases involving missing and murdered Native women. It requires the departments of Justice, Interior, and Health and Human Services to seek recommendations from tribes on enhancing the safety of Native women. It requires new guidelines for responding to these cases, in consultation with tribes. It requires that statistics on missing and murdered Native women be included in an annual report to Congress.

The bill is named for Savanna LaFontaine-Greywind, a 22-year-old indigenous woman who was abducted and killed in North Dakota in 2017. She was pregnant, and her baby was cut from her womb.