Carter's Tragedy

DCI Carter and his team are yet again called upon to deal with the deaths of four victims' the team followed up after uniform officers responded to 'shots fired' in the Kensington area of the city.
The officers attended at a derelict property in beech Street. They found four bodies, two in the downstairs lounge, and two upstairs in one of the bedrooms. All had been shot in their backs, and in the back of their heads.
Carter's team noticed that the four victims were dressed I new clothes, yet they were found in utter squalor. Another four victims are found in two major parks all having the same MO.
Whilst carrying out his investigation Carter receives a call late at night, he immediately attends at The Liverpool Royal, were he meets a smartly dressed man, who tells Carter he is the son of, Kathy Clark an infamous prostitute, and drug addict. Kathy had asked Carter to try and trace her son placed in care, and Carter had found him, the man standing in front of him.
Kathy Clark was in the trauma unit and demanded to see Carter she had been badly beaten up, and manages to tell Carter of a drug gang who are using young teenagers to act as mules in the shifting of drugs up and down the country. Kathy passes away as a result of her injuries.
Carter's team act on information and set up surveillance, which involves the team following two mules up to Glasgow. Due to an error in the force control room the leader of the gang follows Carter's team who are following the mules hoping they would lead them to the gang leader.
Unfortunately the team are boxed in at a junction and attacked by fire bombs and explosives. Carter and his team mates are taken to hospital. The team realise they have a fight on their hands.
Eventually Carter realises that he is dealing with a psychopath who knows no bounds, he is hell bent in getting his drugs out, and doesn't care who he treads on, killing anyone who gets in his way.
One such morning Carter, is sent for by, Tony Frost the Commander of the CID. Carter enters his office to be told that the gang had attacked his flat killing his wife's protection officer, his wife and two young babies. Carter throws himself into driving the team to find the culprits.
He is told there is a conflict of interest, but asks if he can manage and advise the team, yet not get involved in any enquiries. Carter has to resign to the fact. The team driven by his number two DI Susan Ford continue to make headway in this terrible case.