According to Justia, felony murder rule is a rule that allows a defendant to be charged with first-degree murder for a killing that occurs during a dangerous felony, even if the defendant is not the killer.

FBI’s Supplementary Homicide Report

One of the murder circumstances in the FBI’s Supplementary Homicide Report is narcotic drug laws. It is basically unlawful sales of drugs according to here. A more detailed description can be found on the Office of Justice Programs website at here: murders categorized under narcotic drug laws are murders that occur during a felony narcotics offense (such as drug trafficking)

Murder Cases in 33 Large Urban Counties, 1988

E12: $ owed for crack house rent - this Wikipedia page points out that crack houses are often rented informally. Therefore, it is difficult to collect rent through legal channels.