ABC13 learned there is a history of concern about the aviation obstruction lighting - the red flashing lights at the top - on the tower located at Engelke Street and Ennis Street. Though surveillance video from the deadly crash shows a light on at the top of the tower, the lights don't appear to be fully functional.
On Tuesday, NTSB investigators and members of the Houston Fire Department tactical rescue team were on scene to continue collecting evidence. In the afternoon, portions of the helicopter had been excavated and hauled off. NTSB investigators are expected to reconstruct the chopper as part of its standard investigation.
Eyewitness News tracked down the company that owns the tower, SBA Communications out of Boca Raton, Florida. They bought the tower just last month and said they were not aware of any lighting issues.
ORIGINAL REPORT: Child among victims killed when helicopter crashed into radio tower in Second Ward, police say
Child among 4 killed in helicopter crash in Second Ward, officials say
Experts we spoke to, including SkyEye reporters Tammy Rose and Don Armstrong, say they have noticed a trend of lighting problems on the tower in the past.
"It looked like the beacon was on, but the surrounding lights were out. I've been flying here in Houston for seven years, and it has been a problem at least three times when I was flying; my pilot had to report to the tower that the lights were out," Rose said.
With the background of downtown Houston behind the tower coming up from the south, Armstrong said the tower would be almost impossible to see unless you knew it was there.
A longtime pilot who spoke to ABC13 explained that it's every pilot's responsibility to see and avoid all obstacles -- either by going around or going over.
SEE ALSO: Lights on tower hit in deadly helicopter crash had history of not working, SkyEye crew says
Authorities have not confirmed the identities of the four people who were killed in the crash -- including one child.
The NTSB said the Robinson R44 II helicopter was on an air tour flight when it crashed. Flight records show the helicopter made dozens of short trips recently, including five on Sunday before the deadly crash.
Officials said the private helicopter took off from Ellington Field, but it's unclear where it was headed. The crash happened just before 8 p.m. on Sunday.
There are many homes and businesses in the area where it crashed. Thankfully, the helicopter didn't hit anything else on the way down, and officials said no one on the ground was hurt.
As part of the NTSB's investigation, officials are collecting witness statements and any surveillance video of the crash. You can submit those at witness@NTSB.gov.
If you see any debris, you are asked not to touch it and call authorities.