Edge of Tomorrow: How did the aliens finally know that Tom and Team J went to the Louvre to kill Omega?

Because aliens have the ability to go back in time, although the protagonist got this ability at the beginning of the film, the protagonist was sent to the hospital for blood transfusion after being injured, thus losing this ability, and the aliens took back their ability.

Because the protagonist has lost this ability and can't go back to the past. He took the J team to kill aliens, maybe more than once. The aliens may have gone back in time when they were about to be killed, but the protagonist has lost this ability, so he doesn't know that they have been here. The protagonist has also guessed this situation in the movie (on the plane) and made arrangements, although it didn't succeed.

You can watch it again. The plot is quite complicated, but it is very beautiful and the theme is quite novel, which reminds me of the rebirth novel I read recently.