Dr. Kermit Gosnell is on trial, charged with murder, in the deaths of a female patient and four babies prosecutors say were born alive at the Philadelphia abortion clinic he ran. A look at the case:

The investigation. In 2010, federal agents who were raiding Gosnell's clinic in search of drug violations instead stumbled upon "deplorable and unsanitary" conditions, including blood on the floor and parts of aborted fetuses in jars. State regulators shut down the Women's Medical Society clinic and suspended Gosnell's license.

The grand jury report. A nearly 300-page grand jury report released in 2011 described Gosnell's clinic as a filthy, foul-smelling "house of horrors" that was overlooked by regulators. Prosecutors said Gosnell made millions of dollars over three decades performing thousands of dangerous abortions, many of them illegal late-term procedures. The clinic had no trained nurses or medical staff other than Gosnell, yet authorities say many administered anesthesia, painkillers and labor-inducing drugs.

The charges. Gosnell was charged with eight counts of murder until a judge threw out three of the charges Tuesday. He still stands accused of first-degree murder in the deaths of four newborns and third-degree murder in the 2009 death of a 41-year-old Bhutanese refugee who prosecutors say received lethal doses of sedatives and painkillers. He also is charged with violating Pennsylvania abortion law by performing abortions after 24 weeks, operating a corrupt organization and other crimes. Prosecutors are seeking the death penalty in the infant deaths.

The defense. Gosnell's defense lawyer, Jack McMahon, disputes that any babies were born alive. He has suggested that the woman who died, Karnamaya Mongar, had undisclosed respiratory problems that could have caused fatal complications.

The trial. Proceedings began March 18 and are expected to last about two months. Gosnell's former employees have testified that they were just doing what their boss trained them to do and described long, chaotic days performing gruesome work for little more than minimum wage. An assistant testified she snipped the spines of at least 10 babies at Gosnell's direction, sobbing as she recalled taking a cellphone photograph of one baby she thought could have survived.