HOUSTON (AP) — A helicopter crashed Sunday in Houston, killing four people on board and destroying a radio tower, officials said.

The helicopter went down just before 8 p.m. in Houston’s Second Ward, east of the city’s downtown, after taking off from Ellington Field, which is about 15 miles (24 kilometers) away, Mayor John Whitmire said at a news conference. He didn’t know its destination.

The National Transportation Safety Board said in a social media post that it was investigating the crash of the Robinson R44 II helicopter.

The private helicopter with four people on board, including a child, either struck a cable or the tower, Houston Police Chief J. Noe Diaz said at the news conference. As far as officials know, there was no one on the ground when the crash occurred, he said. The identities of the victims and their ages have not yet been released.

Firefighters at a nearby station heard the crash and responded, Whitmire said. Area residents were safe, but there was a “terrible accident scene” with multiple fatalities and the tower and helicopter were destroyed, Whitmire said. Some area residents lost power, Whitmire said.

“It is surrounded by residences and that’s where we were very fortunate — that it didn’t topple in one direction or another,” Whitmire said.

A large area of grass caught fire, but no nearby residences were damaged, just the tower, according to Fire Chief Thomas Muñoz.

“The helicopter that crashed in Second Ward was not an HPD helicopter, it was a private touring helicopter,” Houston City Councilmember Mario Castillo said on X, although that could not be immediately confirmed.

Police and fire officials have urged residents near the crash site to call 911 if they find anything on their property that could help in their investigation. In addition to the NTSB, the Federal Aviation Administration, Department of Public Safety and Houston fire and police were involved in the investigation, officials said.