BUFFALO, N.Y. (AP) — A 17-year-old western New York girl has pleaded not guilty to murdering her step-grandfather.

Alexandria Heath appeared in Erie County Court Thursday, along with her 20-year-old boyfriend, Romaine Jirdon. He also pleaded not guilty.

The couple is accused of beating, stabbing and robbing 58-year-old Thomas Heath in their Buffalo home in November.

Jirdon is charged with first-degree murder, and faces up to life in prison without parole if convicted. Heath, charged with second-degree murder, could receive a sentence of 25 years to life if convicted.

Jirdon's lawyer, Paul Dell, says Jirdon intervened when he found Heath beating his girlfriend and things got out of control. Heath's lawyer, Brian Parker, didn't speak to reporters.

Jirdon and Heath are being held without bail.

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