PHOENIX - The murder trial for a Phoenix woman accused of helping suffocate a 10-year-old girl in a plastic box began Monday.

Samantha Allen is accused of helping her husband, John Allen, lock their niece Ame Deal, 10, in a plastic storage box and leaving her outside overnight.

Deal was found dead the next day. The punishment happened in the middle of July in 2011, and temperatures had reached over 100 degrees that day. The box had only a few small holes.

Opening statements in Allen's murder trial began Monday afternoon, with prosecutors laying out the details of the case and explaining to the jurors that it all began over a box of popsicles. Prosecutors told the jury Allen locked Deal in the box as a punishment for taking a popsicle without asking.

But Allen's attorney argued that the form of punishment, while not regularly accepted in society, was commonplace in the house and was done at the request of Deal's aunt, Cynthia Stoltzmann.

In a surprise move, the defense argues that while Samantha Allen was almost certainly guilty of child abuse, she was not guilty of murder.

John and Samantha Allen are both charged with first-degree murder and child abuse. The girl's father, David Deal, previously pleaded guilty to attempted child abuse and was sentenced to jail. Her grandmother Judith Deal was also sentenced to jail time for her role in the abuse. Deal's aunt Cynthia Stoltzmann was sentenced to 25 years in jail for attempted child abuse.

The prosecution will be seeking the death penalty for both Samantha and John Allen. John Allen's trial is expected to start in August.