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By Wonderwall Editors

Although the Los Angeles Coroner's office has ruled Russell Armstrong's death a suicide, his sister believes the former "Real Housewives of Beverly Hills" cast member was murdered.

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In a series of high profile interviews this week, Laurie Armstrong Kelsoe has voiced her concern that her brother's death is not being treated as foul play. She maintains that more investigation is needed into what actually happened before he was discovered dead in his home on Aug. 15, apparently having hanged himself.

"Not one of us — his family — believe he committed suicide," Kelsoe told earlier this week. "We just don't believe that's what happened at all." Declaring her intentions to alert the authorities, Kelsoe added, "I'm going to call the D.A.'s office."

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On Wednesday, it was revealed that Armstrong, who had suffered from depression following a separation from his wife, Taylor, was not under the influence of drugs or alcohol at the time of his death - a fact CNN's Nancy Grace has suggested supports Kelsoe's theory that her brother did not kill himself.

"It wasn't an option, the way we were raised and our beliefs ... as a Chiristan family, suicide was not an option," Kelsoe told Grace.

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"I just now have started standing up for what I have said all along in private. I didn't want to start all this before the funeral, but it was in the works."

Kelsoe has also appeared on the "Today" show to discuss her belief that Armstrong, 47, was murdered.

Armstrong's family is reportedly now seeking the assistance of a private investigator to determine the cause of his death.

The Sept. 5 season premiere of "Real Housewives of Beverly Hills" included a segment about Armstrong's death, which, according to The Hollywood Reporter, appeared to have contributed to it becoming the highest-rated episode in the show's history.