The Scotland Yard police in the UK used a low tech approach to gain data from the iPhone of a criminal, Gabriel Yew. Undercover officers trailed the suspect, and robbed the phone from him just as he was making a phone call. Then officers in the squad kept manually swiping the screen to prevent the phone from locking up, till the incriminating data was recovered from the phone. BBC has reported one of the most innovative methods of gaining access to the data in an iPhone by law enforcement authorities.
Source and detailed article:
Scotland Yard grabs a criminal's iPhone and keeps swiping to prevent screen lock and access data – Tech