Pat Garrett was murdered in 1908, quite a few years after he killed Billy the Kid. A rather silly movie, with Bob Dylan's musical score, and Bob himself standing around in scenes looking moronic, tried to relate Garrett's death to the Kid's, but the murder was unrelated.
Pat Garrett's daughter wrote the song, "O Fair New Mexico," which is the State anthem. Grade school kids are generally made to sing it, but never more than once- it's banal as banal can be.