NEW You can now listen to Fox News articles! A Florida man is scheduled for execution next month after his conviction in the killing of his cousin's girlfriend and her 4-year-old daughter under a death warrant signed by Gov. Ron DeSantis Wednesday. Richard Knight, 47, will die by lethal injection at Florida State Prison in Starke May 21 as part of a series of death warrants signed by the governor. Knight was convicted in the 2000 murders of Odessia Stephens and her young daughter, Hanessia Mullings, according to WFLA. Prosecutors said Knight and Stephens were involved in an argument the night of the crime. Authorities described the killings in court records as "heinous, atrocious and cruel," the outlet reported. FLORIDA DEATH ROW INMATE USES LAST WORDS TO MAINTAIN INNOCENCE BEFORE EXECUTION Richard Knight, 47, is scheduled to die by lethal injection at Florida State Prison in Starke May 21.…