A man accused of deserting an eight-month-old baby in a residence that reeked of marijuana — a drug that the man was allegedly selling — was arrested Wednesday.

A surveillance operation outside a house at 1869 Southland Court led detectives to the baby's mother, who said she had just seen Richard Alexander Antunez, 27, inside the house with the infant on Wednesday, according to a Baton Rouge Police report.

Antunez was later spotted leaving his house without the child, and the woman told detectives he must have left the child alone inside, the report says.

The woman gave detectives written consent to enter and search the residence, according to the document. Inside, an officer immediately smelled a strong marijuana odor, the report says.

The baby, who had had brain surgery two weeks prior and needs constant care, was found in the residence unattended, according to the report. Officers also found 10 pounds of suspected marijuana and a 9mm Intratec "Mac 10" gun inside the house, the document says.

Antunez was arrested when he returned to his residence and was booked into the East Baton Rouge Parish Prison on counts of possession with intent to distribute marijuana, firearm possession with a controlled dangerous substance and child desertion. His bond was set at $21,000, according to jail records.

Baton Rouge Police Department spokesman Sgt. Don Coppola said the baby boy is now in the care of his mother.

Follow Maya Lau on Twitter, @mayalau.