MONTGOMERY COUNTY, Texas -- Federal investigators are working to determine what caused Channel 13's helicopter to crash in Montgomery County, while the families of the pilot and photographer killed mourn, KPRC Local 2 reported Tuesday.

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Slideshow: Channel 13 Fatal Helicopter Crash

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KTRK's SkyEyeHD helicopter went down in the W.G. Jones State Forest along Peoples Road near F.M. 1488 near Magnolia, Texas, at about 11:15 a.m. Monday.

The National Transportation Safety Board removed all of the helicopter debris from the site to piece it together and find out what caused it to crash.

Investigators said they will look at a variety of factors in determining the cause, including weather reports, autopsies and the pilot's record.

The helicopter was flying to the scene of an officer-involved shooting at the time of the crash.

Pilot John Downhower and photographer Dave Garrett died in the crash. Downhower was employed by Helicopters Inc. and Garrett was employed by Metro Traffic.

Local investigators said the men were apparently thrown from the helicopter.

"He died doing exactly what he loved," brother Jim Downhower said. "First it was airplanes and then helicopters and he was dual-rated. That was his dream."

Wife Lisa Downhower said she knew the risks about flying and accepted them

"He was the best human being that anyone ever, ever could know," Lisa Downhower said. "If you didn't know him, then you missed out. He was the perfect person."

The Downhower family has been through a lot in the past month. Their home was damaged during Hurricane Ike, Lisa Downhower was in a traffic accident and the family dog died.

"I wouldn't wish the last 30 days on anybody … that they've had to endure," said Ron Aguilar, Lisa Downhower's father. "Now she has to do it alone."

According to Channel 13, John Downhower did not make a distress call.

John Downhower often flew Sky 2 for KPRC Local 2. His last flight for KPRC Local 2 was on Friday.

The helicopter, a 1993 Bell 206L4, belonged to Helicopters Inc. Helicopters Inc. was founded in 1978 and leases aircraft to about 70 news organizations around the country, including KPRC Local 2.

Helicopters Inc. and Rolls Royce, the company that made the helicopter's engine, are participating in the investigation.

Lisa Downhower said a memorial service for John Downhower will be held in California and his ashes will be spread near a spot where he liked to surf. Another service will be held in The Woodlands on Friday.

A memorial service for Garrett is scheduled for Saturday.