GAITHERSBURG, Md. (AP) — Montgomery County Police say a woman killed her 5-year-old son with an overdose of a common antihistamine and set her car on fire with him in it.

Officers announced Friday that 33-year-old Narges Shafeirad has been charged with first-degree murder and arson in the death of her son, Daniel Dana.

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On June 16, police and firefighters responding to a vehicle fire in Gaithersburg found Shafeirad lying outside the car. Investigators say her son was in the back seat and was pronounced dead after the fire was put out.

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Investigators say an autopsy showed Daniel died of Diphenhydramine intoxication and ruled the death a homicide.

Police on Thursday served a warrant on Shafeirad, who was burned over 40 percent of her body, at an unidentified medical facility.

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