Karim Ali was a civilian who was mistakenly shot dead in part of a Counter Terrorism operation.
Background
Personal
At some point in his life Ali married his wife, Aaliyah. The two then illegally immigrated to the UK, settling in the unnamed city where the show takes place. They later had a son together. At the time of his death, Ali lived in Flat 59 Regal Court.
Series 1
A Disastrous Affair
In an operational mistake made by the Strategic Firearms Command and Counter Terrorism, armed police officers mistakenly break into the Ali's flat (59) instead of the intended one (56).
Preparing to take his son out in a baby harness, Ali is shot and killed by Sgt. Colin Brackley when he turns around to respond to the sound of his door being kicked in. This was due to Brackley and the other Authorised Firearms Officers mistaking the baby harness for a suicide vest.
Series 4
Episode 1
The death of Karim Ali is mentioned briefly by FC Tim Ifield when he visits AC-12 to voice his concerns about DCI Roz Huntley. He claims the fact the DS Steve Arnott was the only member of the operation who refused to cover up the shooting makes him trustworthy to share information with.
Series 5
Episode 2
DS John Corbett is seen reading about the death of Ali whilst reading through the record of DS Steve Arnott on the Central Police Portal. The notes on Arnott's record cite his willingness to tell the truth and go against his team was fundamental into his recruitment into AC-12 by Superintendent Ted Hastings.