As investigators in the East Village building explosion continue to probe the cause, new details are shedding some light on what they may be focusing on.

Sources tell NY1 there was no authorized gas service to the apartments above the sushi restaurant on the ground floor of 121 Second Avenue, where the deadly explosion took place.

That means any gas service to those apartments was the result of a tampered line.

Investigators are focusing on whether gas was improperly siphoned from a line serving the sushi restaurant.

In August, sources say Con Ed discovered an unauthorized tap on the line that allowed gas to reach apartments upstairs.

Sources say the utility shut gas service until the tap was removed.

Con Ed was at the site again just before the blast for a scheduled inspection.

Investigators are now looking into whether a contractor might have moved to install or reconnect another unauthorized tap on the gas line after the utility left.

Two people were killed in the blast.

The funeral for Nicholas Figueroa, 23, is set for Monday in Manhattan.

Investigators believe the second body pulled from the wreckage is Moises Locon, 27.

That body has not yet been positively identified.