Extract 2

          TIJUANA : Nine people in Mexico were caught red-

          handed on Tuesday digging a tunnel that was apparently

          to be used to sneak drugs into California, officials siad. The

          detainees had been digging from inside a house in the north-

5        west border town of Tijuana and tried in vain to flee, the

          National Defence secretariat said. The tunnel was about

          20m underground and reachable by climbing down a

          ladder through a closet in the house. Army troops also seized

          a truck that the detainees had been using to take away soil

10      from the digging operations. APP

The word that (line 9) refers to the       .