Police officers have been criticised for their actions during the investigation of an Ashford sex attacker, which allowed him to strike again.

Five unnamed officers, including a detective constable and a detective inspector, were reviewed by the Independent Police Complaints Commission (IPCC) for their handling of the case into pervert John Williams - who has since been jailed for assaulting more than 20 women.

Although the police watchdog found that only two officers had cases to answer, in total four of the five will be subject to “management action”.

Scroll down for video

This can include a number of options where the officer’s line manger sets expectations regarding future conduct and identifying any training opportunities.

The IPCC first launched their investigation in January 2014, following a request from Kent Police.

Initially two officers were served with gross misconduct notices amid concerns they had failed to take a vital DNA sample from Williams when he was first identified as a suspect in autumn 2012.

It is understood that a member of the public had recognised him in an e-fit released by police during their hunt for the sex fiend.

However, the tip-off was not acted on, and he went on to attack two more women before he was caught.

In May 2014, another three members of police staff were served with notices from the IPCC for their actions in the case.

The officers under review were not suspended and continued to work for Kent Police during the IPCC’s investigation.

Now, more than a year later, the IPCC has concluded its investigation and found two officers had cases to answer.

It found that a detective constable had a case to answer for misconduct for failing to complete a DNA test in a reasonable time, or alternatively submitting it for reallocation to a colleague.

As a result, Kent Police proposed management action for the detective, which is currently being carried out.

"If you scream, I'll rape you" - John Williams to his victim

The IPCC also found a detective inspector had a case to answer for misconduct, as it was his responsibility to ensure investigative actions were completed.

However, as this officer retired prior to the IPCC’s investigation, he therefore did not face any misconduct proceedings.

The watchdog found no case to answer for the other officers.

However, on reviewing the IPCC report Kent Police considered there was a need for learning for a detective sergeant and a detective chief inspector in their supervision and management roles and therefore proposed management action for them.

In addition Kent Police identified one further officer who failed to record information properly, and it was considered this officer could learn from this and therefore also proposed management action for them too.

Williams, a married father of Essetford Road, South Ashford, was jailed for life, with a seven-year minimum term to be served, after appearing at Canterbury Crown Court in May 2014.

He had previously pleaded guilty to sexually assaulting more than 20 women and teenage girls between November 1991 and August 2013 as they walked along pathways in secluded wooded areas, mostly in Ashford.

His method of operation was to approach women from behind and put his hand over their mouths before molesting them.

One of his victims, a 17-year-old schoolgirl, was attacked in June 2012 in Millennium Woods in Ashford.

Another 18-year-old victim was told by the attacker: “If you scream I’ll rape you.”

Williams was caught after Kent Police launched a large-scale manhunt when they linked three sex attacks which took place within the space of one year.

In total, three e-fit images were released by the force in an attempt to track him down.

Over the course of the operation, DNA evidence was collected from more than 80 men, 5,000 leaflets were given out and more than 100 schools, shops, and businesses were visited.

KentOnline's sister paper the Kentish Express also offered a £500 reward for any information leading to his arrest and an appeal appeared on the BBC’s Crimewatch programme.

The investigation by the IPCC revealed that in the autumn of 2012 Williams was identified as a suspect after a member of the public recognised him from one of the efits.

"The investigation specifically focused on the investigative steps taken from September 2012 and whether they were conducted in a timely manner" - Kent Police spokesman

But no DNA was taken by police at the time, and Williams went on to commit two further sex attacks.

Eventually, he was interviewed by police in September 2013, and a DNA sample was taken, which matched him to sexual assaults in 2012. He was later arrested and charged.

The two attacks in 2013 involved assaults on a 16-year-old in Tunbury Wood, Walderslade and on a 22-year-old near Singleton Lake, Ashford.

A Kent Police spokesman said: "In January 2014, Kent Police asked the Independent Police Complaints Commission (IPCC) to review its response to information received by officers investigating a series of sexual assaults which had taken place in the Ashford and Chatham areas between 2010 and 2013.

"The investigation specifically focused on the investigative steps taken from September 2012 and whether they were conducted in a timely manner.

"The officers under review were not suspended and continued to work for Kent Police in alternative roles while the force assisted the IPCC with its investigations.

"At the conclusion of the review, the IPCC found two officers had cases to answer.

"Both the IPCC and Kent Police have agreed that one detective constable will face management action for failing to complete a DNA test in a reasonable time.

"A second officer, a detective inspector, was found to have a case to answer for misconduct as it was his responsibility to ensure investigative actions were completed. The officer retired prior to the IPCC’s review and therefore has not faced a misconduct hearing.

"Although the IPCC found there is no case to answer against three other officers, Kent Police has decided to take the opportunity to implement management action in their cases to improve learning and understanding.

"Throughout the IPCC review, Kent Police has remained in contact with the IPCC assisting with its investigations.

"Both the IPCC and Kent Police have remained in contact the victims in the criminal case to keep them updated on any developments."

Watch: The day's news on KMTV