The man who confessed to the "Bind, Torture, Kill" murders in the US had a sexual motive in picking his first victims, a sentencing judge has heard.
Dennis Rader was caught by police in February
Killer Dennis Rader told police he targeted Josephine Otero, 11, because he was attracted to Hispanics.
Rader, a former church leader, pleaded guilty in June to the murders of 10 people in the city of Wichita in Kansas between 1974 and 1991.
He faces up to 175 years in jail in a hearing which is set to last two days.
Kansas state had no death penalty when the murders were committed.
Special agent Raymond Lundin gave the court details of a police interview conducted after Rader's arrest in February.
Relatives of victims had to hear very distressing testimony
"He said that he has always been attracted to Hispanic looking people - dark eyes, dark hair, dark skin. He said Josey was the one who caught his eye and she was his target," Mr Lundin said, noting that Rader also told him he was attracted to "younger women".
"I don't know how you call an 11-year-old a younger woman," Mr Lundin said.
Josephine, her father, her mother, and her nine-year-old brother were strangled in their home in January 1974.
Mr Lundin said Rader told authorities he did not think the males would be home.
Victims' relatives will be able to confront Rader for the first time at the hearing, and will tell the judge about their grief.
Rader is also expected to address the court and told a local TV station he was preparing an "emotional" statement.
Prosecutors have said they will present a number of witnesses at the hearing, along with a computer presentation showing photographs of the crimes and other evidence.
"Some of it will be graphic," a spokeswoman for the county district attorney's office was quoted as saying by AP news agency.
Most of the Rader's victims were women, often strangled in their homes.
After the killings, local media later would receive rambling letters claiming responsibility for the killings from a person who named themselves BTK for "Bind, Torture, Kill".
Rader, 60, a father of two, was caught in February this year after a TV station received a letter from a person claiming to be the BTK killer.
He later described how he would hunt for victims to satisfy his sexual fantasies, referring to the killings as his "projects".
He told a local television station that his troubles began when he was at school, and his tendencies ought to have been spotted at some point.