Mary Jones, an 18-year-old high school girl, quarreled with her boyfriend, Thomas Smith. At 3 a.m. following the evening of their quarrel, Mary went to Smith's home to return his picture. Smith stated that after receiving the picture, he went to his room, went to bed, and awoke about 8 a.m. When he looked out his window, he saw Mary's car parked out front. Looking into the car, he discovered Mary sitting erect behind the steering wheel, shot through the chest, a 22-revolver lying beside her on the front seat. She was dead- apparently a suicide. The revolver has been a gift to Mary from her father. Smith called the police to report the shooting.

Mary had been shot once. The bullet entered just below the right breast, traveled across the front of her body, and loaded near her heart. The medical examiner theorized that she did not die immediately. When found, she was sitting upright in the car, her head tilted slightly backward, her right hand high on the steering wheel, and her left hand hanging limp at her left side.

When questioned, Smith steadfastly denied any knowledge of the shooting. Mary's clothing, the bullet from her body, and the gun were sent to the FBI laboratory for examination. An examination of her blouse where the bullet entered failed to reveal any powder residues. The bullet removed from her body was identified as having been fired from the gun found beside her body.

Answer the two following questions:

1. Is the shooting likely to be a suicide or a homicide?
2. What facts support this?
3. How should the investigation proceed?