SANTA ANA (CBSLA.com) — Serial killer Brett Thomas was denied parole on Friday, forcing him to remain behind bars for at least another seven years.

In 1977, Thomas and Mark Titch went on a nine-day killing spree.

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Aubrey Duncan and his daughter Denise were two of the four people killed.

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Titch died in prison, but Thomas, now 56, was asking for parole.

Lynette Duncan went to the parole hearing, along with the Orange County district attorney, and urged the board not to let Thomas out.

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He can appeal for parole again in seven years.