Continuity mistake: While playing the piano in Justin Guthrie's apartment, he is bare handed. In the next scene when he gets up to point at the blood, he is wearing gloves. (00:24:12 - 00:24:42)
Other mistake: When Sherlock and Watson look at the coffee order from the trial it has the names of the 4 jury members who robbed the vault. Not the original men that did the robbery.
Answer: I'm the same person who asked this question. I discovered it was Molly Price whom I recognized from Third Watch.
Cathrine R
It should be noted Donna was Jim Fowkes‘ secretary. Donna killed Peter.
Bishop73