Four dead in US helicopter crash

A helicopter has crashed on to a highway in the US state of Maryland and burst into flames, killing all four people on board, officials say.
No vehicles were hit when the commercial aircraft came down on Interstate 70 in western Maryland.
Firefighters found the helicopter engulfed in flames when they arrived at the scene on Thursday night.
Visibility was said to be limited because of fog, but it was not clear if weather played a part in the crash.
Storms had passed through the area earlier in the night, the Associated Press reports.
Emergency services received a call about the crash at 2230 local time, Washington County emergency services director Kevin Lewis said.
Mr Lewis was among the first on the scene of the crash, west of the Washington County-Federick County line.
He said the helicopter was a Robison R44, four-seat commercial aircraft.
The highway has been shut in both directions and an investigation is underway.