Joan Smith: It was right to question Milly's father in court

While the Dowler family deserves every sympathy, scrutiny of the victim's family life was a necessary part of the legal process

It is sad but not unusual for the aftermath of a sensational criminal trial to focus on entirely the wrong issue. But seldom has it happened so dramatically as in the three days since Levi Bellfield was convicted of the abduction and murder of Milly Dowler, the 13-year-old girl who disappeared as she walked home from school in Walton-on-Thames in 2002.

Milly's killer is a horrible man, a pitiless misogynist who went on to bludgeon two young women to death and tried to kill a third. He has a lengthy history of rape and domestic violence and the question highlighted (not for the first time) by last week's trial is why he wasn't recognised as a danger to women long before he escalated to murder.

We will probably never know the true extent of Bellfield's crimes. In 2008, when he was convicted of murdering Amélie Delagrange and Marsha McDonnell and the attempted murder of Kate Sheedy, the CPS decided there was no public interest in pursuing a series of rape allegations against him. But instead of looking at the toxic combination of excuses, denial and terror that allowed Bellfield to beat and rape women for so many years, the overwhelming response to the end of his trial has been to criticise the way Milly's family, in particular her father, Bob Dowler, were treated in court.

Being cross-examined in a murder trial is a traumatic experience for close relatives. Milly's mother, Sally, said her family had lost their right to privacy, while Bob Dowler described giving evidence as a "truly mentally scarring experience on an unimaginable scale". The Government's Victims' Commissioner, Louise Casey, attacked the family's treatment by Bellfield's defence team as "appalling". Yesterday the Chief Constable of Surrey, Mark Rowley, added his voice to the concern expressed about the family's experience of the criminal justice system.

There is a problem here. First, no matter how ghastly Bellfield is, he is entitled to a defence. Second, the "extremely personal" matters raised by his barrister, Jeffrey Samuels QC, were distasteful but relevant in a trial which turned on misogynistic attitudes to women. As well as looking at the movements of known sex offenders who lived near Milly's home, detectives would have been remiss if they had not scrutinised the behaviour of people close to her.

They became suspicious of Bob Dowler when the following facts emerged: he kept pornographic material at the bottom of a chest of drawers in his bedroom; Milly was hugely distressed when she came across a magazine containing "probably extreme pornographic material... a fetish nature... latex and bondage" a few months before her disappearance; Dowler lied to detectives about his movements on the day of his daughter's abduction, failing to tell them that he stopped at a motorway service station to view pornography; he kept further "extreme" material in a desk in the hallway and in a sitting room; he kept bondage gear in a box in the loft, including a rubber hood and a ball-shaped gag.

Even if Milly hadn't disappeared, it is hard to see why possession of such material by the father of two teenage daughters should ever be treated as an entirely private matter. Looking at extreme pornography and acquiring restraints for use during sex are worrying behaviours, and it isn't hard to imagine circumstances – a custody battle, for example – in which they might even be interpreted as potentially abusive. Indeed, what is so extraordinary about the outpouring of sympathy for Bob Dowler is that so many commentators have been willing to overlook what this might imply about his feelings towards women, while rightly denouncing Bellfield's misogyny in the strongest possible terms. It is possible to sympathise with the Dowler family over the dreadful loss of Milly without arguing that the entire trial process is in need of an overhaul.

Bellfield's hatred of women and violence towards them was well-known among his partners, acquaintances and co-workers. Girlfriends lived in terror of his violence, which included beatings, being burned with cigarettes, rapes, and, on at least one occasion, a hammer attack. His ex-wife says he boasted about raping women, even claiming that he'd lifted a disabled woman out of her wheelchair before assaulting her on the bonnet of his car. A man who worked with Bellfield at a club in Maidenhead, Berkshire, recalled that he gave the date-rape drug Rohypnol to a young clubber before raping her in the car park and stealing her mobile phone. Witnesses who gave statements before his first trial in 2008 recalled more astonishing incidents, including an occasion when Bellfield offered to sell his 16-year-old girlfriend and her younger sister for sex.

Selling girls is as much a crime as rape, which Bellfield openly boasted about, so why wasn't he repeatedly reported to the police? One acquaintance described Bellfield as an "animal", but that's another way of avoiding the issue of criminality. It seems more likely that this is an extreme example of the way in which abusive and even criminal conduct is tolerated within some social groups.

When men like Bellfield are finally apprehended, there's usually a history of abusive behaviour which has gone unchecked over a long period. But a consistent failure to respond to danger signals allows them to get jobs where they come into contact with the public. The Soham murderer, Ian Huntley, was accused of having under-age sex, an indecent assault and four rapes before he killed Holly Wells and Jessica Chapman; he never appeared in court and was able to get a job as a school caretaker. Bellfield was a wheel-clamper but he also worked as a nightclub bouncer, presenting himself as an authority figure to whom girls could turn if they needed help.

There is no doubt that the conclusion of Bellfield's trial has raised difficult and distressing issues. But the most important lesson is that we stop regarding men like him as enigmas, totally disconnected from the society they live in, and understand the existence of a spectrum of abuse. Domestic abuse and rape are serial crimes, committed over and over again with escalating violence, but they're often associated with other behaviours that aren't necessarily illegal: humiliating remarks, defacing images of women, using prostituted women, sex tourism.

When such conduct goes unchallenged by friends, family and co-workers, it becomes normalised and excused. Bellfield was a serial sexual predator before he was a serial killer, and he should have been stopped long before he killed poor Milly Dowler.