FLAGSTAFF, Ariz. (AP) – New FBI statistics show the vast Navajo Nation saw a sharp increase in the murder rate in 2013 and finished the year with 42 homicides, eclipsing major metropolitan areas with less space and far more people, such as Seattle and Boston.

About 180,000 people live on the reservation that spans 27,000 square miles in Arizona, New Mexico and Utah. It's a place where culture and language thrive but where jobs are scarce, alcoholism is among the greatest social ills, and cycles of violence and lack of access to basic necessities can stifle people's spirits.

When those factors combine, “you're always going to find higher crime rates,”said McDonald Rominger, head of the FBI's office in northern Arizona. “There's a correlation.”

The number of people killed on the Navajo Nation increased from 34 in 2012, representing a per-capita murder rate of 18.8 per 100,000 people – four times the national rate. The FBI has not yet released a national murder rate for 2013.

Not a single day passed in 2013 before the first incident of deadly violence was reported on the Arizona portion of the reservation, a murder-suicide in Sanders along Interstate 40. Three more people were killed on the Arizona portion that January, according to court documents.

A man was stabbed at home in Dilkon after he made an inflammatory comment about a gay couple, according to court records. Another man shot his nephew with a rifle in a Red Valley neighborhood after an argument while they were drinking. A 4-year-old girl died from brain injuries she suffered when her caretaker repeatedly hit her over the head while wearing a boxing glove.

When someone is killed on the reservation, FBI agents work the case with Navajo police and criminal investigators. The FBI has jurisdiction over a limited set of major crimes on reservations when the suspect, victim or both are American Indian. Taking a case to federal court doesn't preclude the tribe from also prosecuting. But the penalties under tribal law for homicides are far less stringent, with a maximum sentence of one year in jail and a $5,000 fine even for the most brutal crimes.

The FBI typically opens between 75 and 100 death investigations on the Navajo Nation each year, Rominger said. They are further classified as resulting from an accident, natural causes, a crime and self-defense, for example.

The crimes are among the roughly 250,000 calls that 280 Navajo police officers respond to each year, Navajo President Ben Shelly said recently. Shelly said the ratio of officers per 10,000 people is far less than half that of similar non-reservation rural areas in the U.S.

Greg Jon Secatero, acting criminal investigations supervisor in Tuba City on the Navajo Nation, said that leaves authorities with little time to focus on preventing crimes. More education and resources for people with drug and alcohol problems, or who have a tendency to abuse their family members, might result in fewer people being killed on the reservation, he said.

On the other hand, victims sometimes are in denial or put more emphasis on keeping around the breadwinner or caretaker than protecting themselves, he said.

“We have a problem,” he said. “We need to not look the other direction.”

Navajo Nation homicides far exceed those on other tribal lands around the country. The neighboring Rosebud Sioux and Pine Ridge Indian reservations in South Dakota, with a combined population of about 32,000, each had at least three criminal homicides each in 2012, according to FBI documents provided to The Associated Press through a Freedom of Information Act request. However, parts of the document were redacted, leaving an incomplete picture of the actual number of homicides.

More often than not, homicides on the Navajo Nation are not a result of gun violence.

In one case, a man told authorities he beat his girlfriend to death with an electric cable and his fist after she told him she cheated on him. He then buried her in a shallow grave in Red Valley in March 2013. The man pleaded guilty to second-degree murder and is serving a 20-year prison sentence. Other killings involved a broken beer bottle and an ax as weapons.

In 2013, the number of homicides on the reservation about the size of West Virginia topped Boston's 40 and Seattle's 32, both cities with more than 600,000 residents. Cities with populations similar to that of the Navajo Nation logged far fewer homicides in 2012. According to the FBI's data reporting site, Tempe had 11; Amarillo, Texas, had 10; Tallahassee, Fla., had 12; Columbus, Ga., had 17; and Oceanside, Calif., had eight.

Rominger said authorities typically identify a suspect in reservation homicide cases and find the victim's body within 48 hours. Common factors in a majority of crimes stemming from the reservation are alcohol and domestic violence.

Most defendants enter into plea agreements with federal prosecutors, avoiding trials that take place far off the reservation in major cities like Phoenix, Salt Lake City and Albuquerque, N.M., Assistant U.S. Attorney Patrick Schneider said. Not all homicides will result in prosecution, such as domestic violence cases with an element of self-defense that make a murder conviction tough to achieve.