Authorities have made an arrest in the death of an infant in the Tama County town of Chelsea. Assistant Tama County Attorney Richard Vander May says the child was a full-term newborn baby girl. The medical examiner says the cause of death was strangulation and exposure. Vander May says the baby was also burned, but that will not be listed as the cause of death.Seventeen year-old Nicole Plum, a Chelsea resident, is being charged with first degree murder in the case. Vander May says Plum will be charged as an adult, and she will have the right to ask for the case to be transferred back to juvenile court.Nicole Plum is a student at South Tama High School. The infant, which was named “Baby Chelsea”, was found dead in the snow on February 4th.