Story highlights Between four and six people are believed dead, NTSB says

Ex-Microsoft executive was aboard the plane, a family member says

Two children, ages 1 and 13, are believed to have been in the house

It was not immediately known if anyone was in the plane along with the pilot

A former Microsoft executive and his son were aboard a turboprop airline that crashed Friday morning into two houses in East Haven, Connecticut, a family member told CNN.

There has been "no official confirmation or positive identification" that Bill Henningsgaard and his son were on board, but there is no reason to believe that it was not the two of them, his brother, Blair Henningsgaard, said.

Also feared dead in the crash were two children -- ages 1 and 13 -- in one house, East Haven Mayor Joseph Maturo Jr. said. The other house was unoccupied.

National Transportation Safety Board investigators cannot confirm the number of people killed, saying there are reports of four to six people dead.

Connecticut Gov. Dannel Malloy said there could be as many as five people killed in the crash, including up to three people on the plane.

But Blair Henningsgaard said only his brother and his nephew were believed to be on the plane.

Two bodies were seen inside the home but haven't been recovered because the home is unstable, East Haven Fire Chief Douglas Jackson said at a press conference Friday afternoon.

Fire consumed both houses, preventing firefighters from searching for victims, Jackson said, and the basement in the home holding at least two victims was filled with water.

Maturo said the children were in one house with their mother when the plane struck shortly before 11:30 a.m. The mother escaped, he said.

"It's ... total devastation in the back of the home," Maturo said.

The multi-engine Rockwell International Turbo Commander 690B, registered to Bill Henningsgaard, took off from New Jersey's Teterboro Airport on Friday morning and crashed while approaching the Tweed New Haven Airport around 11:25 a.m., the Federal Aviation Administration said.

The plane missed its initial approach, which isn't uncommon, said Tweed airport manager Lori Hoffman-Soares.

But NTSB investigator Robert Gretz told reporters it was possible the plane was on its first approach.

The neighborhood is about a half mile from the airport. One resident said the accident wasn't surprising.

"They fly in very low, and a lot of times you can hear the engine cut off before it gets to the runway," she told CNN affiliate WTIC

The mayor said the airport's close proximity to residents isn't unusual.

"It's always a concern, but it's something that happens in every airport," Maturo said.

Neither the pilot's identity nor information about how many people were in the plane was immediately available.

The fuselage entered one of the homes, Malloy said. The right wing of the airplane could be seen in the smoldering wreckage of one house, and the left wing was in another house.

Video from affiliate WTNH showed smoke rising from a heavily damaged house in East Haven, and what appeared to be the tail of a plane nearby.

NTSB investigators will examine whether the weather played a role in the crash. It was raining at the time of the crash.

Bill Henningsgaard worked for Microsoft for 14 years, beginning in 1988. He served as vice president of sales for the western United States, Australia and New Zealand.