1.Police investigators substituted Palmer’s bag for a smilar one, then followed him to his hideout.
Gramatically speaking, I can make this paraphrase with "replace":
2.Police investigators replaced a similar one with Palmer’s bag, then followed him to his hideout.
But I don't think that's what investigators usually do. So I'm confused. I want to make sure which bag is with Palmer after the substitution. Thank you.