RIVERTON -- The 13 homicides in Fremont County last year are the most in the county since 1888, county Coroner Ed McAuslan said.

The county's homicide rate for 2008 is 5.8 times the national average, according to an annual report by McAuslan. He based the figure on the U.S. Centers for Disease Control and Prevention 2005 national statistic of 6.1 homicides per 100,000 people.

However, McAuslan said he could not disclose how he classified the deaths of three teenage girls found last June outside a home on the Wind River Indian Reservation. Investigators have refused to release details about the case.

Although McAuslan has completed his report into the girls' deaths, he has said he may never release more information because of federal laws prohibiting disclosure of juvenile cases in investigations.

McAuslan's report noted no suicides among youths in the county last year.

McAuslan also could not release the classification of the deaths of three children who perished in the Aug. 7 fire at a Riverton mobile home park. He said he's awaiting results of the investigation into the fire.

"They are pending right now completion of the investigation," he said. "Until the sheriff's office completes their investigation then I cannot categorize them."

McAuslan said he could not pinpoint what made 2008 such a prolific year for homicides in Fremont County.

"I think if there's any common denominator it's probably substance abuse, but other than that there's nothing specific that I can relate to," he said.

Deaths related to drugs and alcohol accounted for nearly 21 percent of all county coroner cases in 2008 and about 60 percent of non-natural deaths in the county, according to his report.

While authorities will not comment about the possibility of drugs or alcohol involved in the deaths of the three girls, Northern Arapaho leaders in the weeks after launched a major effort to curb substance abuse among teens on the reservation.