I work at a local grocery store, and i was wondering what are my rights to catch shoplifters? I have caught 2 so far.

Both were women, one had a purse. When she walked in her purse was nice and small. As she was leaving it was nice and bulky (no, she didn't go through any cashier). I waited until she walked outside, then asked her to show my manager her bag. She hesitated, walked back in the store and said she did not finish shopping. A minute later (literally) the cart she used was filled with groceries and her bag was nice and small again. I was wondering, did i really have to right to do this? Was this a proper procedure? If not, then what are?

Second, a woman with a baby stroller. She walked in, i see the stroller, the baby, and underneath, a flat baby bag (literally, the bag was flat). She went through my line (im a cashier) and only bought 1 can of baby formula. As she walked out, i looked at the stroller, the baby bag was bulky and full. I waited until she walked out of the store, i then asked her to show the contents of the baby bag to my manager. She started crying and saying how she didn't have money, and emptied the bag. Sure enough, she had food for the baby, along with more baby formulas. Some frozen food, and alcohol. Was i right for asking her to show the contents to my manager? Is this proper procedure, did i go against her rights? What are the proper rights/laws in doing so?

I am asking this because my manager told me i couldn't do that. Even though i notice their bag to be empty/flat, but when they leave the bags are full and bulky. What can i do in case i encounter this again? My store manager said we can get sued, but i am not aware why. I am hoping for someone to educate me.

Rosetta Stone Spain Spanish Version 3