HOUSTON (AP) -- An Amber Alert issued in Fort Bend County has been canceled after a 6-week-old boy was left at a Houston fire station.

The Fort Bend County Sheriff's Office says the infant was dropped off, by an unknown male, on Thursday morning.

Child Protective Services says the baby, described as "filthy" and with a soiled diaper, was in fair condition.

The whereabouts of the mother, 30-year-old Sonia Diane Quintanilla of Needville, is unknown.

Investigators say Quintanilla, who has a history of drug use, had not been heard from since Monday morning while taking her son, Elijah Ray Farris, to a doctor.

Quintanilla, who previously disappeared for short periods of time, did not appear to take food, clothing or diapers for the baby.

Needville is about 37 miles southwest of Houston.

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