Having immigration enforcement is legitimate and not illegal. The way the government was doing it was, at times, illegitimate and illegal.

The app... I don't at all understand what the role of the app is, so I really can't comment on that aspect of the situation.

Calling what ICE is doing "immigration enforcement" is beyond the pale. Administrative warrant are made up take-my-word-for-it notes ICE writes for themselves. Putting kids in cage immoral by any measure. Detaining citizen for days at a time is against the law. Constantly lying about why your summarily executed anyone is a power no law can grant.

...That's what these investigations intend to establish. That's how investigations work.