Once a search is initiated, you cannot destroy data.
He didn't, though. He gave an officer a couple numbers. This action did not destroy any data. The phone could still sit in an evidence locker, all data intact, even after this action.
The officer entering that number into the phone is what destroyed the data. You could argue that he aided in the destruction of evidence. But in that case you need to put the officer on trial as well for destruction of evidence.
Now the officer will claim "I didn't know". In which case you'd ask "then what the fuck were you doing there, not knowing? Does procedure not require you to handle evidence with care? If you didn't know what you were doing, how does that constitute care?"
But, of course, this isn't what's happening. Considering the actual facts, I mean. What's happening is that the government wants the right to spy on you and this dude defended his privacy. And we can't have that, can we? So my money is on the court siding with the police, because they're all part of the same system whose primary purpose is to keep itself intact.