1 of 2
Jeffrey D. Allred, Deseret News
A photo of Kailey Vijil is displayed during a candlelight vigil in West Valley City Sunday, July 19, 2015. Police say Vijil was killed by a 15-year-old neighbor.

WEST VALLEY CITY — Search warrants in the investigation of a 15-year-old boy accused of luring a 12-year-old neighbor from her home and killing her confirm reports that police believe the girl may have been sexually assaulted.

Kailey Vijil was found dead in a horse pasture near her home July 17 after investigators say the 15-year-old knocked on her door after midnight and asked her to help look for his cat. The teen now faces an aggravated murder charge filed in juvenile court.

Kailey was found naked lying on her back in the field, her Batman pajamas near her body, and an article of clothing wrapped around her neck, a newly released search warrant states. Evidence on her body, including blood and fresh scratches, signal a possible sexual assault, police wrote.

Investigators searching the teen's home seized a pair of shoes that appeared to have blood on them, which the boy was wearing at the time of his arrest, and a pair of shorts with a reddish stain, the warrant states.

No sexual assault charges have been filed, and Salt Lake County District Attorney Sim Gill declined to say Friday whether any will be considered.

"We can't speculate to any charges, we can't comment about the substance of it," Gill said. "As with any criminal matter of this complexity, we continue to do our due diligence and I think it's important for people to note and not speculate about it."

On the night Kailey disappeared, her mother sought out police after about 90 minutes of calling her daughter and beginning to search for her. The officers found Kailey's body in a field near 3600 South and 5200 West just before 3 a.m. by "pinging" her cellphone.

Police and neighbors said the boy had attempted to lure other young girls out of their homes before he knocked on Kailey's door. An hour before approaching Kailey, police said the teen asked another young girl to help him find his pregnant cat. The girl's relatives didn't let her leave the home.

A medical examiner determined that Kailey was strangled. The Deseret News reported last month that police were investigating a possible sexual assault connected to the killing. Gill said then that additional charges could be filed in the future, but he declined to say whether police had gathered evidence of a sexual assault.

Prosecutors have requested that the teen be certified to stand trial as an adult, a process that Gill said could take months. The Deseret News has chosen not to name the 15-year-old at this time.

The teenager had previously been referred to juvenile court three times for misdemeanors and infractions in the past 10 months, according to court records. He was arrested for investigation of possession of drug paraphernalia in October of 2014, theft in February, and burglary nine days after his theft arrest.

He was first placed in Salt Lake Juvenile Detention in February and spent 32 days there, according to court records. The boy was placed in an "observation and assessment facility" on May 26. He spent 44 days there before he was released and placed on probation July 9, about a week before Kailey was killed.

Twitter: McKenzieRomero