Fire officials said that an outside investigation was not needed.

"This has become an issue of national security, and I think an investigation is needed."

This is something that needs investigation, and I may need you later on.

But remember this was only the first day and it will need investigation.

Right now there were much more important things that needed investigation.

A fellow who was going to need very close investigation.

He said the investigation "may be needed to get to the bottom of all this and clear the air."

Further investigations were needed to find out, whether this was the only cause.

There was about to be another death that would need investigation.

Clearly, a thorough investigation is needed to look at such questions and to test the police account of the events.