A 13-year-old honor roll student from Florida has been arrested for allegedly stabbing his mother to death as she slept next to her newborn daughter, authorities said.

Derek Rosa has been charged as a minor in the killing of his mom, 39-year-old Irina Garcia, but police in Hialeah publicly identified him because he faces a felony count of second-degree murder.

The shocking incident began unfolding around 11:30 p.m. Thursday, when Rosa called 911 to report that he had “just murdered his mother,” said Lt. Eddie Rodriguez, a spokesman for the Hialeah Police Department.

Officers raced to the family’s apartment on West 79th Street and found Garcia dead in her bedroom, just inches away from a crib containing her 14-day-old daughter, who was unharmed, police said, according to reporting by the station WSVN.

Authorities said they believe Rosa waited until his mother fell asleep before knifing her multiple times in the neck.

Rosa was very polite and apologetic in his interactions with the emergency dispatcher and the responding officers, and “not what you’d think or expect walking into that home or seeing that crime scene,” Rodriguez said.

The 13-year-old murder suspect was described as a straight-A honor student enrolled in the 8th grade at iMater Charter Middle/High School.

Rosa, his infant half-sister and their mother were the only three people at the apartment Thursday. The teen’s stepfather, a truck driver, was away in Georgia at the time.

Rosa had no known history of mental health issues and was said to have been getting along well with his stepfather. There was no record of police responding to the family’s apartment before Thursday, officials said.

Neighbor Lazaro Rodriguez told the station Local 10 in Spanish said that Rosa was “always with his mom” and seemed “calm.”

“He would help her carry packages or shopping bags,” Lazaro Rodriguez said. “I never saw anything abnormal with him. I don’t know what could’ve happened.”

A photo that has been shown by local news outlets depicted Rosa and his stepfather dressed in matching light-pink polo shirts and khakis lovingly cradling Garcia’s baby bump during an idyllic maternity photoshoot before the birth of her daughter.

Investigators have yet to determine a motive for the heinous matricide. Rodriguez said the teen “did not provide any information as to why he did what he did.”

“It’s something we’re all asking ourselves now,” the police spokesman added.

Following his surrender to the police, Rosa was taken to a juvenile detention center, and later to a hospital after he allegedly threatened to harm himself. The 13-year-old made his initial court appearance Friday.