A Bronx mother who faked her infant son’s abduction earlier this week was charged with murdering him and dumping his body in a Queens garbage can, officials said yesterday.

Initially, 25-year-old Lucila Rojas claimed that 3-week-old Anthony Rojas had been snatched from her at gunpoint in front of Jacobi Medical Center on Monday, police said. In subsequent interviews with police, however, Ms. Rojas said her son died en route to visiting relatives in Jackson Heights. She said she abandoned his body in a trash can near 100th Street and Northern Boulevard, police said.

But yesterday, police said they believe Ms. Rojas smothered the baby with a blanket on New Year’s Eve, the day he was released from Jacobi after being born prematurely on December 17. Officials say she then took the bus to Queens, where she placed Anthony’s body in a plastic bag and trashed it.

Afterward, she continued on to her family’s home, police said. “It is our understanding the family didn’t know she was pregnant,” a detective investigating the case, Lieutenant Anthony Mattola, said. The abduction hoax occurred on a day when Ms. Rojas was due at Jacobi for Anthony’s one-month checkup.

In a statement yesterday, the Queens district attorney, Richard Brown, called the allegations “heartless and heartbreaking.”

Last night, Ms. Rojas was awaiting arraignment on charges of seconddegree murder, endangering a child’s welfare, and violating laws for a decent burial. If convicted, she faces 25 years to life in prison.