about seven
o'clock
rumbled Lepardo , crawling away into the outside office , and apparently following a trail visible only to himself . `` It is Mr. Julius Rohscheimer , '' explained Simons . `` He was a partner , I understand , of the late Mr. Graham 's . He entered with a key about seven o'clock and discovered the murder . '' `` As he came in our friend the assassin go out , '' cried Lepardo . Harborne gave rapid orders to the two constables , both of whom immediately departed . `` Are you sure of that , sir ? ''