WHITE PLAINS, N.Y. (CBSNewYork/AP) — An attorney for a woman accused of killing her son with salt says the boy’s high sodium level was caused by his medical treatment.

Defense lawyer Stephen Riebling said in his summation Thursday that 5-year-old Garnett Spears was allowed to become dehydrated — then was given a salty IV fluid.

Lacey Spears, 27, of Scottsville, Kentucky, is being tried in New York on murder and manslaughter charges. She and Garnett lived in Chestnut Ridge at the time of Garnett’s death.

Riebling said the prosecution’s failure to allege a motive “offends our senses.” He also accused police of botching the investigation, WCBS 880’s Marla Diamond reported.

Riebling also tried to cast doubt on the medical examiner’s finding that high salt was the cause of 2014 death.

As CBS2’s Lou Young reported, Spears wept as her attorney pleaded on her behalf, painting a picture of a devoted mother who tended to her son, even in his final hours.

“She played with him, she got him coloring books, she dressed him, she put two pairs of socks on him so he could play on the floor and he wouldn’t be cold. If she was planning on killing him why would she care how cold his feet were?” Riebling said.

Riebling said the prosecution edited video footage to eliminate tender scenes between the mother and child, and Spears was so upset by Garnett’s 2014 death that she considered suicide.

Prosecutors say Spears fed her son large amounts of salt through a gastrointestinal feeding tube, causing brain swelling, seizures and death. They believe she administered the salt in his room at Nyack Hospital after he was admitted for seizures. He later died after being transferred to Westchester County Medical Center.

Prosecutors have said Spears purposely sickened the boy to gain attention and called her “a calculated child killer.”

Jurors saw a video that showed Spears taking her son into a hospital bathroom with a connector tube and the boy suffering afterward. But the defense brought out that some scenes had been edited out.

A feeding bag found in Spears’ apartment had the equivalent of 69 McDonald’s salt packets in it, a forensic toxicologist testified. The defense implied the bag could have been tampered with.

There were no defense witnesses, but Spears’ lawyers extensively cross-examined several prosecution witnesses, attempting to show there could have been other causes for the boy’s death.

The prosecution rested on Tuesday and the defense announced Wednesday that Spears would not testify.

Doctors testified that there was no medical explanation for the extremely high level of sodium in Garnett’s body and that a child fed in an ordinary fashion would spit out that much salt. But Garnett had a feeding tube because his mother told doctors he could not keep food down otherwise. Prosecutors said Spears, who documented her son’s hospital and doctor visits on social media, claimed the boy had illnesses he did not have.

Westchester County Assistant DA Patricia Murphy said Spears tortured him and sought sympathy on social media.

“She didn’t care if he lived or he died as long as her need for attention to be the center of everybody was met,” Murphy said.

A friend of Spears told the jurors that after Garnett died, Spears asked her “to go to her house and get a feeding bag in the middle of the room and throw it away and not tell anybody.”

The Spearses lived in Chestnut Ridge, a suburb north of New York City, at the time of Garnett’s death. Lacey Spears moved to Kentucky afterward and was living there when she was arrested.

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