Arlene Arkinson was a victim of the Troubles. Her lonely death wasn't sectarian, nor the work of paramilitaries; yet she was a victim of the conflict and the climate it created. That has become apparent in the Police Ombudsman report on the investigation into the 1994 disappearance of the 15-year-old Castlederg girl.

The Ombudsman's Office found that, after Arlene's disappearance was reported, it took 46 days to arrest Robert Lesarian Howard, the convicted rapist and child abuser in whose company she was last seen. Why? Was it police incompetence? A conspiracy? The more likely explanation is that the RUC was so wedded to political policing and its battle against Irish Republicanism, that little effort, resources or commitment were devoted to so-called "civilian crimes". There is also the strong evidence that Howard was a police informant.

The statement from the Police Ombudsman encapsulates the situation: officers quickly identified concerns but "the CID failed to respond with vigour to reports that a vulnerable person was missing and had been seen with a known sex offender". Vital evidence was lost or destroyed and those officers who finally did investigate the disappearance and likely murder were chasing down a cold trail.

Howard was ultimately acquitted of killing Arlene because the jury was not allowed to hear of his criminal past. By the time of his trial, his crimes also included the murder of a 14-year-old girl in England. There is little doubt that he is guilty of Arlene's murder.

In the light of the RUC mis-handling of the case, new questions arise. Had the police acted swiftly, might Arlene have been found alive? We may never know. What we do know is that Howard went on to kill Hannah. That should never have been possible given his atrocious record for sex offences against women and children.

Undoubtedly the culture of political policing failed Arlene and her family, as well as Hannah and her family. The RUC detectives failed to act as any modern police force does when a child disappears – with all due haste to protect life and preserve the scene and the integrity of the investigation. Instead, like political stalkers, they hovered around the investigation until it was too late.

This report is a reminder that the police are there is serve and protect, not to fulfil a political role.