PHILADELPHIA (CNN) -- A jury Monday found a Philadelphia abortion provider guilty of three counts of first-degree murder.
Dr. Kermit Gosnell, 72, was accused of killing babies by using scissors to cut their spinal cords. Authorities alleged that some of the infants were born alive and viable during the sixth, seventh and eighth months of pregnancy.
Monday's first-degree murder conviction means Gosnell, who is not a board-certified obstetrician or gynecologist, could be sentenced to death.
Gosnell also was accused in the death of Karnamaya Mongar, 41, who died of an anesthetic overdose during a second-trimester abortion at his West Philadelphia clinic. In that case, the jury found him guilty of involuntary manslaughter.
Gosnell was also found guilty of 21 counts of abortion of the unborn, 24 weeks or older.
In Pennsylvania, abortions past 24 weeks are illegal unless the health of the mother is at stake.
Earlier, the jury, after deliberating for two weeks, said it was hung on two counts, and the judge instructed them to continue trying to reach a verdict on them.
Judge Jeffrey P. Minehart also told jurors that their progress showed they were "considering the evidence seriously."
Gosnell's co-defendant, Eileen O'Neill, 56, is charged with participating in the operation of a corrupt organization and theft by deception for operating without a license to practice medicine. O'Neill, a medical school graduate, is not charged with performing illegal abortions.
Both pleaded not guilty.
Eight people involved in Gosnell's clinic, called the Women's Medical Society, have pleaded guilty to various charges, including four to murder.
The grand jury report from 2011 says the "people who ran this sham medical practice included no doctors other than Gosnell himself, and not even a single nurse," yet they still made diagnoses, performed procedures and administered drugs.
Defense attorney Jack McMahon, in an impassioned, 2½-hour closing argument, said that none of the infants was killed; rather, he said, they were already dead as a result of Gosnell administering the drug Digoxin, which can cause abortion.
Gosnell also was accused of reusing unsanitary instruments; performing procedures in filthy rooms, including some in which litter boxes and animals allegedly were present at the time; and allowing unlicensed employees -- including a teenage high school student -- to perform operations and administer anesthesia.
The remains of aborted fetuses were stored in water jugs, pet food containers and a freezer at the clinic, the city's chief medical examiner Sam Gulino testified.
Former employee Kareema Cross said Gosnell regularly performed illegal late-term abortions that he routinely recorded as "24.5 weeks." In Pennsylvania, abortions past 24 weeks are illegal unless the health of the mother is at stake.
McMahon, who called no witnesses, accused prosecutors of "the most extraordinary hype and exaggeration in the history of the criminal justice system," even adding that they are "elitist" and "racist."
Gosnell has been accused by authorities of preying on low-income, minority women. McMahon argued that Gosnell offered access to health care for people who were poor and without health insurance.
During his closing remarks, Philadelphia Assistant District Attorney Edward Cameron turned to Gosnell and yelled, "Are you human?"
Gosnell smirked at Cameron without speaking. Cameron then continued, declaring, "It's time for us to extinguish the fire he created."
The doctor was first charged in January 2011.
CNN's Josh Levs, David Ariosto, and Sunny Hostin contributed to this report.
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