How can you tell when an app was redownloaded on iphone?

So I’m on probation for assault charges. I felt like I defended myself, but apparently I took it too far. This guy was threatening me physically, he got in arms distance, I punched him twice, he fell. He got up, grabbed on to me, we were hitting eachother, until I slammed him. He tried getting up again, and I soccer kicked him in his face, breaking his nose. I was charged with simple assault and aggravated assault. I was looking at about 4 years. They said everything was fine up until I kicked him. Regardless, I took a plea deal. Simple assault, 2 years probation. I’m allowed to have social media, but my PO checks it, and I feel as though it’s seriously violating my privacy. I downloaded and deleted my apps. I went to check in, and he somehow knew I downloaded snapchat the day before. I didn’t know you could check the date of apps’s last time downloaded. How do you?

How can you tell when an app was redownloaded on iphone?
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