▁leading ▁to ▁the ▁bank ’ s ▁drive - through ▁counter . ▁Van ▁Ste enberg h ▁decided ▁to ▁dig ▁a ▁tunnel ▁into ▁the ▁bank ▁from ▁that ▁plot ▁of ▁land , ▁under ne ath ▁the ▁emb ank ment ▁and ▁to ▁the ▁found ations ▁of ▁the ▁bank ▁building , ▁from ▁where ▁he ▁hoped ▁he ▁to ▁gain ▁access ▁to ▁the ▁v ault . ▁ ▁Van ▁Ste enberg h , ▁who ▁had ▁no ▁experience ▁in ▁exc av ations , ▁began ▁dig ging , ▁but ▁the ▁tunnel ▁c aved ▁in ▁soon . ▁He ▁made ▁a ▁second ▁attempt , ▁this ▁time ▁carefully ▁sh oring ▁the ▁tunnel ▁with ▁tim bers . ▁He ▁would ▁work ▁during ▁the ▁night ▁and ▁cam ou fl age ▁the ▁tunnel ▁entrance ▁with ▁scattered ▁tw igs ▁during ▁the ▁day . ▁By ▁van ▁Ste enberg h ’ s ▁accounts , ▁his ▁wife ▁was ▁una ware ▁of ▁what ▁he ▁was ▁doing , ▁and ▁he ▁would ▁always ▁provide ▁a ▁cover - up ▁story ▁for ▁his ▁abs ences . ▁ ▁By ▁late ▁October ▁van ▁Ste enberg h ▁had ▁reached ▁the ▁opposite ▁side ▁of ▁the ▁al ley ▁and ▁began ▁to ▁slope ▁his ▁tunnel ▁up wards . ▁ 1 8 ▁feet ▁( 6 ▁m ) ▁into ▁the ▁tunnel , ▁he ▁reached ▁a ▁craw l ▁space ▁under ▁the ▁bank ▁building . ▁From ▁there ▁he ▁managed ▁to ▁get ▁into ▁the ▁bank ’ s ▁cell ar ▁and ▁just ▁under ne ath ▁the ▁v ault . ▁He ▁estimated ▁the ▁v ault ▁floor ▁to ▁be ▁about ▁ 2 0 ▁inches ▁( 5 0 ▁cm ) ▁thick . ▁ ▁In