LITTLETON, Colorado- An Australian woman who died in what police say was a suicide pact with her twin sister at a Colorado shooting range had no drugs or alcohol in her system.

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The Arapahoe County coroner's office told KMGH-TV in Denver Monday that 29-year-old Kristin Hermeler had a history of despondency, but no suicide note was found at the south suburban shooting range where she died Nov 15.

Authorities say her sister, Candice Hermeler, also shot herself in the head at the shooting range, but survived. Investigators say she told them the sisters from Australia's Victoria state had a suicide pact but refused to say why they wanted to die.

Candice Hermeler left a Denver-area hospital in late November.