PHOENIX -- A man accused of killing a 19-year-old Gilbert woman earlier this year made plans to escape from jail with a makeshift key fashioned out of a toothbrush, authorities said.

The Maricopa County Sheriff's Office said Jonathan Burns, 26, admitted to chiseling the plastic toothbrush into a tool he could use to open his handcuffs.

Burns reportedly planned to unlock the cuffs and escape from a transport van.

Burns was arrested in February in connection with the death of Jackie Hartman after police found her bloody, bullet-ridden clothing in a trash bin near his Mesa home.

The Gilbert nursing student had been reported missing the day before, after she failed to return home from a date with Burns. Her body was found Feb. 18 in the desert north of the Valley.

Burns was charged with kidnapping, sexual assault and murder.