▁the ▁burg l ars ' ▁arrest , ▁the ▁F BI ▁discovered ▁E . ▁Howard ▁H unt ' s ▁name ▁in ▁B ark er ▁and ▁Martínez ' s ▁address ▁books . ▁N ixon ▁administration ▁officials ▁were ▁concerned ▁because ▁H unt ▁and ▁L idd y ▁were ▁also ▁involved ▁in ▁a ▁separate ▁secret ▁activity ▁known ▁as ▁the ▁" White ▁House ▁Pl um bers ", ▁which ▁was ▁established ▁to ▁stop ▁security ▁" le aks " ▁and ▁investigate ▁other ▁sensitive ▁security ▁matters . ▁Dean ▁later ▁test ified ▁that ▁top ▁N ixon ▁a ide ▁John ▁Ehr lich man ▁ordered ▁him ▁to ▁" deep ▁six " ▁the ▁contents ▁of ▁Howard ▁H unt ' s ▁White ▁House ▁safe . ▁Ehr lich man ▁subsequently ▁denied ▁this . ▁In ▁the ▁end , ▁Dean ▁and ▁the ▁F BI ' s ▁Act ing ▁Director ▁L . ▁Patrick ▁Gray ▁( in ▁separate ▁operations ) ▁destroyed ▁the ▁evidence ▁from ▁H unt ' s ▁safe . ▁ ▁N ixon ' s ▁own ▁reaction ▁to ▁the ▁break - in , ▁at ▁least ▁initially , ▁was ▁one ▁of ▁ske ptic ism . ▁Water gate ▁pro sec utor ▁James ▁Ne al ▁was ▁sure ▁that ▁N ixon ▁had ▁not ▁known ▁in ▁advance ▁of ▁the ▁break - in . ▁As ▁evidence , ▁he ▁c ited ▁a ▁conversation ▁t aped ▁on ▁June ▁ 2 3 ▁between ▁the ▁President ▁and ▁his ▁Chief ▁of ▁Staff , ▁H . ▁R . ▁Hal de man , ▁in ▁which ▁N ixon ▁asked , ▁" Who ▁was ▁the ▁as sh ole ▁that ▁did ▁that ?" ▁However , ▁N ixon ▁subsequently