The World Federation One Stop Fiqh

Ruling 514

If a person touches a corpse that has been given the three ghusls52 completely, then performing this ghusl does not become obligatory for him. However, if one touches part of a corpse before the completion of the third ghusl, then even if that particular part of the corpse has been given the third ghusl, he must perform the ghusl for touching a corpse.

52 See Ruling 538.