Police are investigating why a mother allegedly abandoned her 5-month-old daughter in a Coney Island apartment building overnight.

Authorities say the baby was left unattended on a doormat in a seventh-floor hallway at O'Dwyer Gardens on West 33rd Street. EMS took the girl to Coney Island Hospital, where she is said to be in good condition.

Neighbors say they heard an argument in the hallway, followed by the sounds of a baby crying hysterically. Some tenants say a small bottle of vodka was found next to the child.

While some neighbors say they have seen the child's mother, known as "Michelle," under the influence in the past, others say the woman took good care of her baby daughter.

The baby's mother was taken into police custody for questioning.