Can I recover a deleted text message from last may? I need it for a police investigation

If you sync Messages with iCloud, no, you cannot recover a deleted text message from May or for that matter any date after the message was deleted.

If you do not sync Messages with iCloud, the ONLY hope you would have is if you had a backup from last May, but that's most unlikely, if you use iCloud to backup your iPhone when it is plugged in to charge and connected to a network.

To know if you sync Messages with iCloud, open the Settings App on your iPhone. Tap your name at the top. Tap iCloud. Tap Show All. If messages is turned on, then you cannot get the message back.

The above applies to iOS 16. If you are on a lower version of iOS, you won't need to tap Show All. Messages will show as either turned on or off.

If this is a case where the police are involved, you need to reach out to Apple, not the community. They can help guide you through what you are or are not able to do.

If the OP syncs Messages with iCloud, Apple will NOT have a copy of a deleted message.