A song about a person falsely accused of killing a cop is not a song about a cop killer.
A song about a cop killer would be a song in which the cop deserved to die, and perhaps recommendations about how bad cops should be killed in the future.
Woody Guthrie sang a famous song about Pretty Boy Floyd, who did kill a cop, I believe. Should anyone who has ever sung this song be excluded from the White House? I used to help run a coffeehouse, and almost all the singers knew this song, as well as songs about Jesse James.
How about this one:
Bonnie and Clyde is a 1967 American crime film directed by Arthur Penn and starring Warren Beatty and Faye Dunaway as the title characters Clyde Barrow and Bonnie Parker. The film features Michael J. Pollard, Gene Hackman and Estelle Parsons, with Denver Pyle, Dub Taylor, Gene Wilder, Evans Evans and Mabel Cavitt. The screenplay was written by David Newman and Robert Benton, adapted from the exploits of legendary crime duo Bonnie and Clyde. Robert Towne and Beatty provided uncredited contributions to the script; Beatty also produced the film. The soundtrack was composed by Charles Strouse.
Shall we exclude all these people from WH invitations as well?