The teenaged monster, 16, abducted, raped and murdered Alesha on the Isle of Bute last year.
Residents on the island claim Campbell was in touch with Zanythe Harrison, 38, who groomed a schoolgirl to perform webcam sex shows for paedophiles.
She avoided prison in 2008 after admitting to directing the shows at a flat in Bute.
A source told the Daily Record that Campbell – convicted last week – spent time at Harrison’s house.
They were in contact “often” before Alesha’s death and were friends, but not romantically linked.
One told the paper: “Obviously Campbell was obsessed with dark things on the web and I’m sure he would have known about Zanythe’s convictions.
“He maybe thought sex offenders don’t get that much of a punishment”
“He maybe thought sex offenders don’t get that much of a punishment.
“This could have played a part in his twisted crime if he thought he would get away with it.”
The webcam victim was served alcohol by ballet dancer Harrison while paedophiles watched on.
She admitted encouraging her to perform, but her lawyer insisted a “Mr X” from England was threatening Harrison and was the main culprit.
Harrison admitted contravening the Protection of Children and Sexual Offences, Scotland Act but charges specifying the sex acts she was asked to perform were dropped.
She was put on the sex offenders’ register.
Campbell is awaiting sentencing and is expected to serve life.
He took Alesha from her bed where she was sleeping, on the Isle of Bute, on July 2 last year.
He inflicted gruesome injuries before dumping her body in a woodland.
She sustained 117 injuries and died form significant pressure being applied to her face and neck.
Lord Matthews told Campbell he had committed some of the “wickedest, most evil crimes this court has ever heard”.