After a series of delays, Missouri executed serial killer Joseph Paul Franklin early Wednesday morning. The white supremacist, who targeted African Americans and Jewish people in a string of grisly murders, was the first man killed by the state using a single drug, pentobarbital. It's the first Missouri execution in nearly three years. 

Franklin's killing spree from 1977 to 1980 left up to 20 people dead, according to the killer's own account of his actions. He also confessed to shooting Hustler magazine publisher Larry Flynt in 1978, leaving Flynt partially paralyzed. But Franklin was given the death penalty for just one of his many confessed attacks: the murder of Gerald Gordon outside of a synagogue near St. Louis. The AP goes into more detail on his crimes: 

Franklin had a particular dislike for interracial couples — several of his victims were black men and the white women with them. He arrived in suburban St. Louis and picked out Brith Sholom Kneseth Israel synagogue from the Yellow Pages. On Oct. 8, 1977, a bar mitzvah ended and guests were in the parking lot when Franklin opened fire from a grassy area nearby, killing Gordon, 42.

Missouri went ahead with the execution, originally scheduled for about 1 a.m. on Wednesday, after the Supreme Court overturned two stays early Wednesday morning. Those stays questioned the state's new lethal injection protocol, siding with Franklin's legal team's argument that the procedure could constitute cruel and unusual punishment. One stay also cited questions about Franklin's competency — he was diagnosed as a paranoid schizophrenic in 1997. The Supreme Court decision allowed Missouri to proceed immediately with the execution. Franklin was pronounced dead at 6:17 a.m. 

Franklin's protest against state procedure stems from the state's improvisation after international drug companies refused to sell it execution drugs. Pentobarbital, the drug used Wednesday, is commonly used to euthanize animals. Since Missouri can no longer buy pentobarbital, , it and other states have started looking for other potential drugs, or other sources of pentobarbital. After scrapping a plan to experiment with using propofol (the anesthetic that likely killed Michael Jackson), Missouri tapped an unidentified, private compounding pharmacy to make pentobarbital for the state's death penalty chamber. You can read more detail on that debate here