It was the lengthiest investigation of any hill fort in western Europe.

He discovered the fate of his biological mother in 2006 after a lengthy investigation.

But after a lengthy investigation the police ruled out foul play.

Mediation is offered as an alternative to a lengthy investigation.

He wondered how his father had felt right before a big arrest after a lengthy investigation.

Its conclusions were based on material that had been made public over the course of the panel's lengthy investigation.

After a lengthy investigation, the charges were dropped in June 2006 because of insufficient evidence.

The accident put a halt to flight tests, and a lengthy investigation began.

Surely, however, this should be done with caution, following lengthy investigation of any potential negative, rather than positive, results?

But a determination of arson is only the first step in what are often lengthy investigations.