"Don't say nothing!"

So yelled Natavia Lowery's mother as she saw what the Daily News calls "the petite suspect" being "hauled off in handcuffs to court." But Lowery had already confessed to killing the wealthy "punk-rock pioneer" Linda Stein. According to the police, she said she "bashed in the Realtor's head with a yoga stick after she blew pot smoke in her face and made a racial crack."

"Get the f---ing e-mails! How can you be so f---ing slow!" Stein supposedly bellowed, a police source said.

Stein, who had private yoga sessions in her $2.5 million pad, was waving a 4-pound strength-building yoga stick at Lowery as she yelled, the assistant told cops.

After Lowery retrieved the e-mails, Stein offered to buy her lunch as a peace offering.

"I've got my own money. I don't need you to buy me lunch," the assistant said indignantly.

"Black people don't have any money," Stein retorted, according to Lowery. "Save your money and I'll buy you lunch."

An enraged Lowery grabbed the yoga stick from Stein and hit her with it a half-dozen times until she was face-down in a pool of blood, police said.

Defense lawyers will have to contend with the fact that Lowery spent a long time calmly cleaning up the penthouse after the bludgeoning,

Her trips in and out were captured on surveillance tape, which showed her nonchalantly carrying out a bag, police said. She checked the bottom of her shoes once after leaving, possibly examining them for blood, sources said.

"She looks quite normal when she's coming in and out of the apartment," said NYPD Detective Antonio Rivera.

Once could argue that she reverted to a robotic mental state. Calmly cleaning up the penthouse makes no sense if you're leaving a brutally beaten body in it. If you were thinking rationally, you'd want the scene to look as if an outsider did it, but an outsider wouldn't clean up. Therefore, Lowery could contend that the calm behavior after the murder was actually evidence of insanity. I haven't read about cases where a theory like that was attempted, so I don't know how well it might play, nor do I know of any scholarly writing in the field of psychology that might support such a theory. I'm just tossing it out as a possibility.

You have to also explain the fact that Lowery stole Stein's ATM card and withdrew $800. I'd say that as a personal assistant, a methodical criminal could have found a much more effective way to extract money from the victim. And with that kind of access, if she had planned to kill Stein, Lowery could have figured out a more insidious way to do it. The fact that her instincts led her to clean up the crime scene seems to indicate that if she were planning the murder, she would have chosen a method that didn't create such a bloody mess.