MIAMI (WFLA) — A Florida mom is accused of strangling her 8-year-old son to death in her car and then running several errands while he was unconscious in the backseat, according to the Miami-Dade Police Department.

Shaneka Ann McKinzie, 36, allegedly confessed to using a black tablecloth to suffocate the child on Tuesday evening while he was asleep in the backseat of her car, according to police. She reportedly had been thinking about it for the past two days.

When the child stopped struggling, McKinzie allegedly removed the tablecloth and proceeded to “conduct several errands throughout Miami-Dade County” for several hours before eventually taking him to a hospital, according to an arrest affidavit.

The child was pronounced dead at the hospital, police said. An autopsy determined he died due to strangulation.

McKinzie was charged with first-degree murder, police said.