A police officer has been found guilty of raping and sexually assaulting a 13-year-old girl.

Ian Naude, 30, who was working as a student officer for Cheshire police at the time of the assault in October 2017, was described during the two-week trial as a “selfish and cruel paedophile” who joined the force with the intention of meeting vulnerable victims.

A jury at Liverpool crown court found him guilty of rape and sexual assault on Thursday, as well as four charges of attempting to arrange the commission of a child sex offence and one charge of arranging a child sex offence, relating to five complainants aged between 12 and 15.

Naude had been acting on an “ever increasing interest in young girls” over the past six or seven years, the court was told. Police believe there may be more victims who have yet to come forward.

He started working for the police in April 2017, despite being named as a suspect in a child grooming case by a neighbouring force in the months leading up to his appointment, it has emerged. Cheshire police have said they were not made aware of the allegations until after he was arrested in November 2017.

Naude, who previously served in Afghanistan as a machine gunner with the Royal Irish Regiment, was warned by the recorder of Liverpool, Judge Clement Goldstone, that he faced a “very significant sentence indeed”.

Summing up, Goldstone said: “The defence concede that this is a case which has fairly depicted the defendant as a cold, uncaring, selfish and cruel paedophile who has on occasion stooped as low as coercive and threatening behaviour, including blackmail of young girls, some of whom have been properly characterised as vulnerable.”

Naude admitted having sex with his 13-year-old victim, whom he met while on duty, but claimed she had consented.

He also admitted two counts of engaging in sexual communication with a child, 14 counts of inciting a child to engage in sexual activity, one count of taking indecent photos of a child, four counts of making indecent photos of a child, six counts of causing a child to watch a sexual act, two counts of misconduct in a public office and one count of possessing indecent photos of a child.

He denied attempting to arrange to commit child sex offences, claiming messages sent to girls asking them to meet him were just fantasy.

Naude, originally from South Africa, had been called to a domestic incident at the victim’s house in October 2017 and contacted her on Facebook days later.

After exchanging sexual images and messages over social media, he took her out in his car and raped her, the jury heard.

The court was told Naude, who was based at Crewe police station, would gain the trust of young girls by posing on social media as a 15-year-old boy called Jake Green.

He also had an account under the name of Bruce Ian Wayne, in an apparent reference to Batman, and a Snapchat account named King Of The North.

He coerced his victims to undress and sometimes perform sexual acts on camera before sending them sexual pictures and video of himself, the court heard.

In some cases he then threatened to send the photos to his victims’ Facebook friends and on one occasion he told a victim he would harass her friends, including one who self-harmed, unless she sent him photos.

The court heard that after the rape was reported Naude was accidentally copied into a police email revealing the plan to arrest him.

When his phone was seized 756 images had been deleted from it.

Other devices, including a laptop and another phone, were later discovered in a field in Market Drayton after he gave a map of their location to his cellmate.

Naude will be sentenced on 13 December.