Authorities have discovered a tunnel beneath an industrial building in Mexico City that fuel thieves dug to tap gasoline and diesel pipelines.
Mexico discovers thousands of such taps each year, but seldom are they found connected to tunnels and seldom are they located in such heavily populated areas.
WATCH: Multiple people killed in Mexico fuel pipeline blast (Jan. 19)
The tunnel was several yards long and deep, and had timber framing to prevent collapse. The tunnel accessed four pipelines that carry fuel to a nearby tank farm.
All had illegal taps drilled into them.
READ MORE: Mexico pipeline explosion death toll rises to 114
Such illegal taps frequently leak and catch fire, as one did Jan. 18 in Hidalgo state, north of Mexico City.
That fire occurred as residents were gathering spilled fuel. The death toll in that fire now stands at 119.