A smirking killer's defiance in the face of a life sentence collided with a pregnant daughter's grief Monday in the murder of rock 'n' roll Realtor Linda Stein.

"My mother will never set eyes upon or hold my baby," said Mandy Stein, who revealed she is four months' pregnant with her first child.

Her gut-wrenching emotion came in stark contrast to convicted murderer Natavia Lowery's cold insistence that she's not guilty.

"This is just the beginning of a new fight ... to get a fair trial," said Lowery, who scoffed at her punishment.

Lowery, 28, got the max of 25 years to life for bludgeoning her boss - plus 2-1/3 to 7 years for stealing $30,000 from her.

She entered Manhattan Supreme Court smirking and refused to look at Stein's two tearful daughters even as they called her "a ruthless killer."

Mandy Stein, 35, said she is still tormented by finding her mother's battered body in an upper East Side penthouse Oct. 30, 2007.

"I am haunted by the images of what I saw that night as well as what I felt - my mother's body, hard as a rock and cold to the touch," the documentary filmmaker said.

Her sister, Samantha Stein, 37, tried arduously to get Lowery, her mother's personal assistant, to look at her.

The unrepentant defendant, wearing a cream linen suit refused to meet her gaze, shuffling papers instead, seemingly indifferent to the tongue lashings.

"Natavia, I am beyond angry with you. You robbed me like you did my mother," Samantha Stein said.

Stein's daughters called their mother "our hero," a breast cancer survivor with the "chutzpah" to succeed as manager of the punk group The Ramones, and later as the favored Realtor to stars such as Madonna.

"You beat her to death," Samantha Stein exclaimed. "You then took every opportunity to smear her good name. You are a disgusting person."

She said her mother would have turned 65 last Saturday, and that this Sunday will be "another motherless Mother's Day."

"You are truly a cold, ruthless killer," she told Lowery.

The sisters said they were "re-victimized" by the behavior of Lowery and her family - who have suggested the daughters had a role in Stein's death.

"I personally was accused by them of carrying out this heinous crime in a confrontation outside this courtroom," Mandy Stein said.

Lowery, convicted Feb. 23 after five hours of deliberations, was unmoved.

She insisted she was railroaded by an "incompetent" defense team and "underhanded tricks" perpetrated in the judge's chambers.

"I was never afforded a fair trial," said Lowery, who was pregnant at the time of the slaying and delivered a baby while in jail awaiting trial.

While professing his client's innocence, newly hired defense lawyer Paul Brenner pleaded for "mercy," asking Justice Richard Carruthers to give Lowery the minimum prison sentence.

Carruthers was unimpressed, ordering her to repay the $30,000 she stole and saying he would recommend she never get parole.

"Ms. Lowery acted with an uncommon and almost inhuman degree of coolness and calculation," he said.

mgrace@nydailynews.com