Whenthetwobrothersarrivedfromtheprovincestorenderthelastsaddutiestotheirsire，theyfoundtheirsisterasgrieved，toalloutwardappearance，asevenfilialaffectioncoulddesire:buttheyoungmenonlycametoperish。TheystoodbetweenSainteCroixandthealreadyhalf-clutchedgo]d，andtheirdoomwassealed。Aman，namedLaChaussee，washiredbySainteCroixtoaidinadministeringthepoisons；and，inlessthansixweeks’time，theyhadbothgonetotheirlonghome。
Suspicionwasnowexcited；butsocautiouslyhadallbeendone，thatitfoundnooneuponwhomtoattachitself。TheMarquisehadasister，andshewasentitled，bythedeathofherrelatives，tohalftheproperty。LessthanthewholewouldnotsatisfySainteCroix，andhedeterminedthatsheshoulddiethesamedeathasherfatherandbrothers。Shewastoodistrustful，however；and，byquittingParis，sheescapedthedestructionthatwaslurkingforher。
TheMarquisehadundertakenthesemurderstopleaseherlover。Shewasnowanxioustoperpetrateanotheronherownaccount。ShewishedtomarrySainteCroix；but，thoughseparatedfromherhusband，shewasnotdivorced。Shethoughtitwouldbeeasiertopoisonhimthantoapplytothetribunalsforadivorce，whichmight，perhaps，berefused。ButSaluteCroixhadnolongeranyloveforhisguiltyinstrument。Badmendonotadmireotherswhoareasbadasthemselves。
Thoughavillainhimself，hehadnodesiretomarryone，andwasnotatallanxiousforthedeathoftheMarquis。Heseemed，however，toenterintotheplot，andsuppliedherwithpoisonforherhusband:buthetookcaretoprovidearemedy。LaBrinvillierspoisonedhimoneday，andSainteCroixgavehimanantidotethenext。Inthismannerhewasbuffettedaboutbetweenthemforsometime，andfinallyescapedwitharuinedconstitutionandabrokenheart。
Butthedayofretributionwasathand，andaterriblemischancebroughtthemurderstolight。ThenatureofthepoisonscompoundedbySaluteCroixwassodeadly，that，whenworkinginhislaboratory，hewasobligedtowearamask，topreservehimselffromsuffocation。Oneday，themaskslippedoff，andthemiserablewretchperishedinhiscrimes。Hiscorpsewasfound，onthefollowingmorning，intheobscurelodgingwherehehadfitteduphislaboratory。Asheappearedtobewithoutfriendsorrelatives，thepolicetookpossessionofhiseffects。Amongotherthingswasfoundasmallbox，towhichwasaffixedthefollowingsingulardocument:——