There were therefore three witnesses who could swear that Mrs. Inglethorp was carrying her coffee, as yet untasted, in her hand. 
In addition to coffee, Mrs. Inglethorp was carrying her lunch bag.
mnli hypothesis: In addition to coffee, Mrs. Inglethorp was carrying her lunch bag. premise: There were therefore three witnesses who could swear that Mrs. Inglethorp was carrying her coffee, as yet untasted, in her hand. 