A former police sergeant has been jailed for a second time after admitting sexual activity with a boy and possessing indecent images.
Phillip Patterson, 34, was sentenced to six years in prison and will be a registered sex offender for life.
Sussex Police say Patterson's latest offending came to light during a routine visit in 2018 as part of his terms.
Judge David Rennie at Hove Crown Court said Patterson was "dangerous".
Patterson, of Alexandra Road, Burgess Hill, West Sussex, already served a prison sentence for possessing more than 50,000 indecent images of children.
He resigned from his position with the police force on the day of his arrest in 2010.
Det Con Vicky Jones said: "During a routine visit in 2018 to Patterson as part of their role to monitor registered sex offenders in the community, colleagues found on his mobile phone references to indecent material about children.
"The phone also contained evidence of his online grooming and sexual relationship with a 13-year-old boy, a relationship which the boy confirmed when we traced him."
He had already been given an eight-week suspended sentence in October 2016 for a previous breach of his sex offender notification requirements, and in September 2018 was given a 17-week custodial sentence for the further breach of the registration requirement which came to light in the police visit earlier that year.
In sentencing Patterson, Judge David Rennie said: "Some people reach for the idiotic justification that 'they're only pictures'.
"In all of these pictures, a child is having their innocence destroyed. Secondly, the 13-year-old, you groomed him and led him into your dark world of paedophilic abuse. I have no hesitation in concluding that you are dangerous."