Unattended child drowns; only the father is arrested

Story here. Whay aren't they both under arrest and facing charges? Excerpt:

'The father of a 14-month-old child who drowned in a uncovered cesspool in the family's backyard is being held on a $5,600 bond.

Michael Wilson, 20, of Somerton, made his initial appearance in Somerton Justice Court Thursday morning via video feed from the county jail.

"I'm going to hold you on bond due to the nature of the offense," said Somerton Justice of the Peace Jorge Lozano.
...
Wilson's child, Aiden Lee Bailey, fell into an open-pit cesspool and drowned Wednesday, according to YCSO. The child was pronounced dead at Yuma Regional Medical Center after lengthy efforts failed to revive him.

The child's mother, Crystal Bailey, 20, was also interviewed by YCSO deputies. YCSO will be asking the Yuma County Attorney's Office to review the case for potential criminal charges against her as well.

An investigation into the case revealed that the child allegedly had been left in the yard, located at 11516 S. Somerton Ave., while the parents were inside the residence.'