Gibson and Burns are hauled over the coals by the Police Ombudsman and the Policing Executive for their conduct and handling of the case. When Spector's name is released to the press as the arrested suspect in the Belfast Strangler case, his wife and family are forced to deal with the consequences. Katie enraged at the media treatment of him, decides to take matters into her own hands. All the while Nurse Kiera Sheridan and the medical team continue to fight to keep Spector alive. But even if he survives will he ever be fit enough to stand trial?

The episode was rated 7.55 from 1835 votes.

When a Belfast murder remains unsolved, Stella Gibson is brought in to catch the killer.

The episode was rated 7.57 from 2028 votes.

As Spector's health stabilises, his legal team, lead by Sean Healy, move into action, determined he will never stand trial. Detective Superintendent Stella Gibson discovers evidence that there may be more victims. Keen to get Spector back into the justice system, Gibson speaks to August Larson, the consultant psychiatrist who will be assessing Spector. Sally-Ann reaches breaking point.

The episode was rated 7.58 from 1774 votes.

DSI Stella Gibson's fears are realised as Spector's murder spree in Belfast continues.

The episode was rated 7.66 from 1702 votes.

It has been ten days since Paul Spector told DSI Stella Gibson that she would never catch him. As Gibson tries in vain to help Spector's surviving victim to remember the identity of her attacker, Spector is forced to deal with the loose ends that he left behind in Belfast. His return to the city reveals that someone from his past has been helping police with their enquiries, forcing Spector to change his plans with terrifying consequences.

The episode was rated 7.70 from 1536 votes.

As DSI Stella Gibson takes control of the hunt for the serial killer striking women in Belfast, the realisation that his perfect kill is tainted pushes Spector into looking for his next victim.

The episode was rated 7.72 from 1621 votes.

Gibson informs Burns that their confrontation in her hotel room may have been witnessed by Spector, and the detective is shocked to discover the serial killer has been paying visits to one of his surviving victims in hospital. Seizing on the opportunity, she finally locates Spector and puts him under surveillance, but her success is short-lived as she is forced to face her worst fears.

The episode was rated 7.73 from 1335 votes.

Spector's legal team are determined that he will never stand trial. Anderson and Ferrington make a discovery from the past that may help Gibson build her case.

The episode was rated 7.74 from 1663 votes.

Gibson orders extensive surveillance on Spector's family, believing they will lead them to Paul, whose whereabouts remain unknown. As the search for Rose Stagg becomes ever more desperate, Spector directs his fury at Gibson after the two narrowly avoid meeting, trespassing into her private world and delighting in taunting and provoking her.

The episode was rated 7.78 from 1395 votes.

Gibson realises that her mistakes have put the life of witness Rose Stagg in danger. Desperate to save Rose's life, she steps up the police investigation as serial killer Paul Spector continues to stalk Belfast's streets.

The episode was rated 7.78 from 1449 votes.

With Spector under surveillance, Gibson wants to make sure that a solid arrest strategy is put in place so that no evidence is lost and the police have the best chance of saving Rose Stagg. However, the killer's unpredictability forces the detective to act quickly as her carefully laid plans fall apart in front of her eyes.

The episode was rated 7.88 from 1365 votes.

When Eastwood's investigation into Olson's murder throws open some uncomfortable truths for Burns, Gibson comes under increased pressure in her hunt for Belfast's killer.

The episode was rated 7.91 from 1526 votes.

The series concludes as Gibson and Anderson put fresh evidence to Spector, with explosive results. Spector's new-found friendship with another inmate develops, with devastating consequences.

The episode was rated 7.93 from 1679 votes.

Gibson arrives at the Annie Brawley crime scene and realises it is the work of the serial killer, while Burns and his team are still trying to piece together the events surrounding Olson's murder. Spector raises Sally Ann's suspicions when he asks her to provide him with an alibi and he decides to make one final play with Gibson that will bring the two hunters closer than either could have previously imagined

The episode was rated 7.98 from 1517 votes.

Gibson's investigation leads her to the killer's lair, but there is no sign of Rose Stagg and the detective instructs her team to step up the interviews with Katie, Sally Ann and Spector in a desperate attempt to find her. However, it is only when Spector makes a final move to remain in control that Gibson is offered any answers.

The episode was rated 8.03 from 1428 votes.