NEW YORK (WABC) --The NYPD is releasing new information on the massive gas explosion that killed a veteran fire chief.
Investigators are still recovering evidence Monday night, six full days after the blast.
Authorities say there is no question that an illegal network of pipes siphoned natural gas and diverted it into the building on 234th Street.
They are working to determine who performed the work and when it was done.
"We found a deviation within the home, in the basement, that we can't explain right now. So we're going to take that out, extract that piping and its fittings and send it down to Maryland to the ATF lab to see what kind of construction went into it, how long it's been there and see if that's the issue. So right now, it's a work in progress," said Robert Boyce, Chief of Detectives.
The explosion last Tuesday leveled the two-story home. 20 people were injured and an FDNY battalion chief was killed.
44-year-old Michael Fahy died while working to evacuate the neighborhood after a report of a gas leak.
His funeral this weekend drew an estimated 10,000 mourners.
Investigators say the home was secretly being used to grow enormous amounts of marijuana.
Two men have been charged in this case, but the investigation is far from over.