Helen Maghi (No. 172) - S9-E16
Factual error: Harold tells Raymond he'll repay the bail money, but given he's pleading guilty and fully intends to go along with required court appearances, etc, the bail money paid will be refunded - it's not like Raymond is out-of-pocket.
Revealing mistake: Aram "hacks" an employee database via a company website - the code that's briefly visible on screen (slo-mo helps but isn't required) is just standard HTML that lays out a web page, not server commands.
Answer: The man Red killed, Sam Scott, was Lizzie's adoptive father, not her biological one. However, at that time Lizzie (and thus the audience), was led to believe her real father abandoned her and her mother, so expect more secrets to be revealed how her real father actually died (or if he's even actually dead).
Bishop73