Richard Avery, 33, is the second person to have been charged over the deaths of William Henry and Brian McIntosh who were killed in Brierley Hill last month.
Jonathan Houseman, 32 and from Stourbridge, has already been charged with their murder.
Mr Henry, 31, and Mr McIntosh, 29, were found dead in a Range Rover on the car park of the Albion Works industrial estate on the afternoon of September 30.
The men, both from the Bartley Green area of Birmingham, are thought to have been gunned down several hours before their bodies were found.
It was the third of three shooting incidents in the Black Country in three days.
Alleged gunman Houseman, of Quarry Park Road, was arrested in Lancashire the day after the men were killed and is due to stand trial in June next year.
Avery, of no fixed address, has been charged with conspiracy to murder and perverting the course of justice and was set to appear at Birmingham Magistrates Court today.
A spokesman for West Midlands Police said: "The victims’ families have been updated with news of the latest charges, and we continue to support them at this tragic time.
"Our investigation continues, and anyone with information has been asked to get in touch."
Anyone with information can call West Midlands Police on 101, or Crimestoppers anonymously on 0800 555111.