Police interrogation video of two Wisconsin girls accused of nearly killing a classmate to please a fictional character shows them describing their calculated plan to kill their friend, telling her they planned to go bird watching.

"People who trust you become very gullible," one of the girls told a police investigator following an attack on Peyton Leutner May 31 in a wooded area of a park in Waukesha, a community about 20 miles west of Milwaukee.

"It was sort of sad," the girl added.

WISN-TV obtained 9 hours of separate videotaped interrogations of the girls, ages 12 and 13. One of the girls wipes away tears as she explains how they hoped to please Slender Man by killing Leutner, who survived 19 stab wounds and crawled to a path near the woods after her attackers left.

"So we told her we were going to get help, but we really weren't. We were going to run and let her pass away. So, we ran," one girl explains to a detective.

The other girl spent about 6 hours in an interrogation room, some of which she sits alone singing to herself.

"We knew it was going to be at my birthday sleepover. You have no idea how difficult it was not to tell anyone," the girl said to an investigator. "Truth be told, I wanted to be locked up so I couldn't hurt her. But, that time has passed and now I'm in here because we were so careless. I knew this would happen. I knew we'd get in trouble."

Both girls described the character Slender Man during their interrogations.

"He was tendrils that are very sharp," one girl said. "I see him in my dreams."

Authorities arrested the girls walking along a highway about 5 hours after Leutner was found a passing bicyclist. They told authorities they were on their way to the Nicolet National Forest in northern Wisconsin where they thought they would join Slender Man in his mansion.

The two girls are charged in adult court with party to attempted first-degree intentional homicide. They each could face up to 65 years in the state prison system if convicted. Their attorneys want their cases moved to children's court where a conviction could send them to a secure facility until age 25.

Waukesha County Circuit Judge Michael Bohren said he intends to issue a ruling in the case March 13.

The Associated Press isn't naming the defendants because their cases could end up in juvenile court. Leutner, who turned 13 last week, had recovered from the attack and returned to school.