Man pleads guilty in beating death of aunt

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William Null By Jennifer Thomas William Null By Jennifer Thomas

PHOENIX -- A 41-year-old man accused of beating his aunt to death after an argument over cigarettes pleaded guilty to second-degree murder and two counts of burglary.

William Null's sentencing is scheduled for June 29.

Cynthia Pesek, 61, was found dead inside her Mesa home in November. Investigators from the medical examiner's office determined Pesek had numerous skull fractures. Authorities said Null beat her to death with a wooden tree stake.

Police officers took Null into custody as he attempted to ride a bike from the area.

Null told police that he had been angry at Pesek because she had embarrassed him in front of their neighbors after he was unable to pay for cigarettes they had purchased for him. Pesek paid for them and Null said the two argued about it for three days.

Null periodically lived with his aunt, who was a retired teacher with Mesa Public Schools.