NEW YORK – Dr. Satish Chundru, a Texas forensic pathologist working for Daniel Penny's defense as he fights charges for the subway chokehold death of Jordan Neely, returned to the witness stand Friday for a second day of grilling.

Penny, a 26-year-old Marine veteran and architecture student, grabbed the 30-year-old Neely in the middle of a schizophrenic, drug-fueled outburst on a subway car that witnesses said included death threats and had them fearing for their lives. Although Neely still had a pulse when Penny let go, he later died.

Contrary to the official autopsy report conducted by Dr. Cynthia Harris of the New York City Medical Examiner's Office, Chundru testified that he does not believe a chokehold caused Neely's death.

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During a grueling cross-examination, Assistant Manhattan District Attorney Dafna Yoran grilled Dr. Chundru on the connection between sickle cell trait and death in other cases, prompting repeated objections from the defense.

At one point, Judge Maxwell Wiley cut her off and said "we’re not doing that." But the questioning continued through more objections before the court went to recess.

Before jurors returned, the defense argued that Yoran improperly brought up the term "homicide," a misstep that happened earlier in the trial as well.

Wiley said he did not want to strike the back-and-forth. When the jury returned, he told them that "homicide" means something different to a medical examiner than it does to a lawyer or a jury and asked them not to weigh the witness’ use of that word when weighing facts of the case.

It was the second time that the word "homicide" came up controversially and prompted the defense to raise an objection. Earlier this week, Wiley ordered the first comment stricken, when Dr. Harris mentioned that "all homicide reports" were reviewed by another doctor in the city medical examiner's office.

Not all homicides are criminal, and the defense argued that the prosecution's repeated espousal of the word could confuse the jury.

The defense asked the court to note for the record that they have had several conversations, and the DA’s office agreed that bringing up testimony from forensic pathologists regarding death as a "homicide" would be misleading to the jury.

The first time, it came from Dr. Harris. The second, the defense said Yoran said the word as part of her questioning. She denied it. The judge said he would review the transcript later and issue additional jury instructions if necessary.

While Penny's team has maintained that his actions were justified, that's not their only line of defense, according to Louis Gelormino, a New York City defense attorney who is closely following the case.

"One of the other defenses is, ‘Well, I didn’t kill him. My actions weren’t the cause of death,'" he told Fox News Digital Friday. "So yes, it doesn’t make a difference if it was justifiable. But if his actions weren’t justifiable, the jury could also say, ‘Hey, [his] actions didn’t kill him. He died because of the other things going on in his body.’ And that’s why that’s relevant."

Chundru, a former Miami-area medical examiner who now runs a private practice in Texas conducting autopsies in a half-dozen counties, has testified that he did not believe an air choke caused Neely's unconsciousness and, therefore, did not cause his death.

Rather, he blamed it on "the combined effects of sickle cell crisis, the schizophrenia, the struggle and restraint, and the synthetic marijuana."

Dr. Michael Baden, a former New York City medical examiner and leading forensic pathologist, disagreed with Chundru's testimony.

"Dr. Chundru's testimony may have been very interesting, but it was wrong," he told Fox News Digital. "He described what can happen in sickle cell disease, not what happens in sickle cell trait, which Neely had. Eight percent of Black people in this country have sickle trait, which is a benign medical condition that rarely causes any symptoms, let alone death."

At the autopsy, Harris found significant "sickling" on Neely's organs, she testified, and lawyers on both sides asked for an explanation. She said the condition did not contribute to Neely's death, and she blamed it solely on asphyxiation from the chokehold. 

"Sickle trait red blood cells do sickle after death, when the body's oxygen supply disappears and can be seen at autopsy – as with Neely or with anyone with sickle trait dying from any condition," Baden said. "It's a post-mortem artifact like rigor mortis. Further, death from sickle disease takes days of sickling to occur; it can't occur in seconds as happened to Neely."

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However, he said, even if the chokehold caused Neely's death, it is not up to the medical examiner to decide whether that was criminal.

"The individual circumstances are important as to whether the death could [or] should have been avoided, and whether the death should be prosecuted, which is entirely up to the prosecutor," he said.

Penny faces up to 15 years in prison if convicted on the top charge of manslaughter. He also faces a charge of criminally negligent homicide.

It was not immediately clear whether he would take the stand in his own defense, although some experts have suggested it is likely that he will because it is a self-defense case.