▁Dis app earance ▁On ▁ 2 8 ▁September ▁ 1 9 2 0 , ▁Gray son ▁was ▁out ▁drink ing ▁with ▁friends ▁when ▁he ▁received ▁a ▁tele phone ▁message . ▁He ▁told ▁his ▁friends ▁that ▁he ▁had ▁to ▁go ▁to ▁the ▁Queen ' s ▁Hotel ▁in ▁Le ic ester ▁Square ▁and ▁would ▁be ▁back ▁shortly . ▁He ▁did ▁not ▁return . ▁ ▁Donald ▁McC orm ick ▁claimed ▁that ▁artist ▁George ▁F lem well ▁had ▁been ▁painting ▁a ▁picture ▁of ▁the ▁Th ames ▁when ▁he ▁saw ▁Gray son ▁entering ▁a ▁house ▁( Number ▁ 6 , ▁The ▁Island , ▁Th ames ▁Dit ton ) ▁on ▁the ▁river ▁bank ▁on ▁ 2 8 ▁September ▁ 1 9 2 0 . ▁F lem well ▁knew ▁Gray son , ▁having ▁painted ▁his ▁portrait ▁before ▁the ▁war , ▁but ▁did ▁not ▁real ise ▁the ▁significance ▁at ▁the ▁time ▁because ▁Gray son ▁was ▁not ▁reported ▁missing ▁until ▁several ▁months ▁later . ▁An ▁investigation ▁carried ▁out ▁in ▁the ▁ 1 9 6 0 s ▁revealed ▁that ▁the ▁house ▁that ▁Gray son ▁entered ▁was ▁owned ▁by ▁Mau nd y ▁Gregory . ▁Research ▁by ▁Andrew ▁Cook , ▁however , ▁suggests ▁that ▁McC orm ick ▁may ▁have ▁fabric ated ▁the ▁story . ▁▁ ▁Gray son ▁was ▁never ▁seen ▁again . ▁It ▁has ▁been ▁spec ulated ▁that ▁he ▁was ▁murder ed ▁to ▁prevent ▁his ▁reve aling ▁evidence ▁of ▁cor ruption . ▁However , ▁a ▁compreh ensive ▁bi ography ▁by ▁David ▁G . ▁Clark ▁suggests ▁his ▁possible ▁surv ival ▁into ▁the ▁ 1 9 5