Israel Keyes was born on January 7, 1978, in Richmond, Utah. He was the second of ten children of Heidi and John Keyes. His parents were part of a strict religious group. When Israel was five, his family moved to a remote area in Washington. They lived in a small cabin without electricity or running water. The family attended a church that had extreme beliefs and became friends with a family whose son later committed serious crimes.

Israel's family later joined another church that had racist beliefs. Their cabin was so small that some of the kids had to sleep in a tent. The children hunted for food and worked on farms to help the family. Israel's strange behavior made other kids avoid him. He liked to hurt animals and once skinned a deer alive, which scared everyone. Israel started doing bad things alone and kept to himself.

Israel also broke into houses, started fires, and stole guns. Once, he tied a cat to a tree and shot it, laughing as it died. His mother noticed he was acting strangely. By his teenage years, he was good at building things and worked as a carpenter. He kept a journal with Bible verses and wrote about feeling guilty for his sins. The family moved to Maine, where they collected sap for syrup. Israel eventually rejected his religious upbringing, which caused his parents to kick him out.

In the late 1990s, Israel assaulted a teenage girl in Oregon. He planned to kill her but let her go instead. He later told investigators that he regretted not being violent enough.

Israel joined the U.S. Army in 1998 and served until 2001. He was stationed in several places, including Egypt. He was quiet and kept to himself but drank heavily on weekends. He received an Army Achievement Medal for his service. After leaving the Army, he moved to Washington and started a construction business in Alaska.

He lived with his girlfriend and had a daughter. When asked if his crimes began after his Army service, he hinted that they did, saying, "Yeah, Neah Bay's a boring town.”

Keyes chose random people all over the United States to avoid getting caught. He spent months planning each crime before doing it. He often went to campgrounds and lonely places. Keyes liked using strangulation because he enjoyed seeing his victims lose consciousness. He claimed he didn't kill children or parents because he didn't want his daughter to find out about his crimes. But the police thought he might have killed teenagers and children.

During his three years in the U.S. Army, Keyes didn't admit to any murders, but he did say he tried to rape two women. One was a sex worker in Egypt, and the other was a college student in Israel. After leaving the Army in 2001, he started killing again. Keyes had connections to New York, where he owned a cabin and 10 acres of land. He also confessed to robbing banks in New York and Texas. The FBI confirmed he robbed a bank in Tupper Lake, New York, in April 2009. He also said he burglarized a home in Texas and set it on fire.

An FBI report said Keyes broke into 20 to 30 homes and robbed several banks between 2001 and 2012. He is believed to have killed up to eleven people in the U.S. and possibly more outside the country. Keyes planned his murders very carefully to avoid detection. Unlike most serial killers, he did not have a specific type of victim. He chose his victims randomly and paid for everything with cash. He had no connections to his victims. For one murder, Keyes flew to Chicago, rented a car, and drove 1,000 miles to Vermont. He used a "murder kit" he had hidden two years earlier to commit the crime.

Keyes confessed to killing three people. He admitted to murdering William "Bill" Scott Currier and Lorraine Simonne Currier in Essex, Vermont. He broke into their home, tied them up, and took them to an abandoned farmhouse where he killed them. Their bodies were never found. Keyes had hidden a "murder kit" near their home two years earlier and used it for the crime. He later moved the kit's contents to a new hiding place in Parishville, New York.

Keyes' last confirmed victim was 18-year-old Samantha Koenig, a coffee booth worker in Anchorage, Alaska. He kidnapped her, took her debit card, and killed her the next day. He left her body in a shed while he went on a cruise with his family. When he returned, he took a photo to make it look like she was still alive and demanded a ransom. After getting some money, he dismembered her body and disposed of it in a lake. The FBI later found her remains.

Keyes hinted at other murders, but their identities are uncertain. In 1996, 13-year-old Julie Marie Harris went missing in Colville, Washington, and her remains were found in 1997. Keyes lived in the area at the time but didn't confirm or deny killing her. In 1997, 12-year-old Cassie Emerson disappeared after her mother's body was found in their burned-out trailer. Cassie's remains were found in 1998. Keyes admitted his first act of arson was with a trailer in Colville.

Keyes claimed to have killed five people in Washington State and was investigated by the state police and FBI. He said he buried or submerged a victim in Neah Bay, Washington, between July and October 2001. He confessed to killing a couple between 2001 and 2005. He also claimed to have killed two more victims between 2005 and 2006, dumping one in Lake Crescent, Washington. In 2012, authorities identified a possible victim, known only as Lewis County Jane Doe, found in Washington in 2011.

Keyes is suspected of being involved in the 2007 "Boca Killer" crimes in Florida, including the murders of Randi Ann Gorenberg and Nancy Bochicchio and her daughter. Authorities believe Keyes may have killed Debra Feldman, a woman who went missing in New Jersey in 2009. Keyes searched for her case online before his arrest.

Keyes is also a suspect in the 2012 disappearance of James Tidwell, an electrician from Texas. During a bank robbery in Texas, the robber wore a hard hat similar to Tidwell's. Keyes admitted to using a wig made of human hair during the robbery.