Updated

A 39-year-old Los Angeles woman was arrested Tuesday on suspicion of stabbing her four-month-old daughter with scissors, leaving her in critical condition, Fox 11 reported.

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The attack unfolded in the University Park area on Tuesday afternoon after the infant’s parents got into an argument, police said. The father was able to disarm the woman, who has since been identified as Mary Mendez, and call 911.

"The mother attacked the baby in front of the dad. We can't imagine why a mother, who is supposed to be caring for her child, could do such a heinous act," LAPD Detective Moses Castillo told local reporters.

The motive of the alleged stabbing remains unknown.

Mendez is being held on $1 million bail at Los Angeles County Jail on suspicion of attempted murder.

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