has been tampering
Presente perfecto progresivo para el sujetohe/shedel verbotamper with.

tamper with

Someone else has been tampering with the system.
Alguien más ha estado manipulando el sistema.
A friend suspects that someone has been tampering with his wine.
Un amigo mío sospecha que alguien le ha hecho algo a su vino.
Somebody has been tampering with it.
Alguien la ha estropeado.
Palabra del día
el guion