The conviction of Mark Bridger for the murder of April Jones has sparked calls for search engines such as Google to do more over "easily accessible" child porn online.
Campaigners have called for more to be done to stamp out the "vile trade" after details emerged of the twisted material hoarded by the 47-year-old paedophile killer.
Jon Brown, of the NSPCC, said: "Google need to do more in terms of blocking searches for child abuse imagery but they also need to alert the authorities if someone is blatantly doing these searches."
The search engine giant told The Huffington Post UK it had a "zero-tolerance policy" on child sexual abuse content.
Keith Vaz, chairman of the Commons Home Affairs Select Committee told The Independent the April Jones case illustrated the "need to act to remove such content from the internet”.
He said new rules for internet service providers were needed to force them to “remove material which breaches acceptable behaviour standards”.
In a file on his laptop marked 'Z0', Bridger held cartoon pornographic images depicting bound and gagged youngsters being sexually abused.
Earlier this month, the Old Bailey heard how Stuart Hazell, jailed for murdering 12-year-old Tia Sharp, had searched for vile child porn on the internet using terms such as "violent forced rape" and "incest".
Campaigners have called for more to be done on online child porn
Phillip Noyes, acting chief executive of the NSPCC, said April's case adds to growing evidence that there is a link between child and extreme porn, and committing other serious sexual assaults.
He said: "It seems Bridger lived in a fantasy world which included looking at child abuse images online.
"For some time we have been concerned about the growing number of these obscene images which are becoming more easily available and can fuel the fantasies of offenders like Bridger.
"This case points to the ever-growing evidence that there is a worrying link between looking at this vile kind of material and committing other serious sexual assaults.
"April's death will hopefully lead to effective measures to stamp out this vile trade."
On Sunday, Mail journalist Amanda Platell wrote about how easily she had accessed child porn images online in an attempt to highlight how easy it was.
The Metropolitan Police said they were "liaising" with the newspaper.
Friday's Daily Mail calls for Google and Microsoft to "block" child porn.
April's case comes after a confidential hotline used to flag criminal content online revealed it had seen a 32% increase in the number of reports of images showing the rape and sexual torture of children.
The hotline, run by the Internet Watch Foundation (IWF) charity, can also be used anonymously to report child sexual abuse content as well as "criminally obscene adult content".
IWF spokeswoman Emma Lowther said about 1.5 million adults have stumbled across child sexual abuse content on the internet - but last year the organisation received just under 40,000 reports.
She said: "The UK is extremely quick and nimble at tackling what is possibly the most horrendous images and videos available on the internet.
"But to use the IWF and the online industry effectively, we need everyone to do the right thing and report to iwf.org.uk.
"Removing the images is by far the best way to prevent people from seeing them. It also prevents the victimisation of the abused children."
The Crown Prosecution Service (CPS) decided not to charge Bridger with offences in relation to indecent images.
District crown prosecutor Iwan Jenkins said: "There was also evidence that Bridger had committed offences relating to indecent images.
"However, we determined that it was not in the public interest to charge Bridger with any additional offences.
Bridger had a stash of child porn on his computer
Last week, the End Violence Against Women (EVAW) coalition wrote to the Prime Minister calling for a change in legislation to close a loophole which allows some simulated images of rape to be allowed in this country.
A statement from charity Rape Crisis, an EVAW member, which campaigns to raise awareness of sexual violence, said it commended the decision to give Bridger a whole life sentence.
It said: "Our concern is that given current legal loopholes, similar men using pornography simulating acts of sexual violence including rape, child sexual abuse and incest, would not be committing an offence under existing extreme pornography legislation.
"An open letter to David Cameron sent by women's groups last week identifies this loophole and asks for it to be closed as a matter of urgency."
Scott Rubin, director of communications & public affairs at Google, said: “Google has a zero-tolerance policy on child sexual abuse content. We are members and joint funders of the Internet Watch Foundation - an independent body that searches the web for child abuse imagery and then sends us links, which we remove from our search index.
"When we discover child abuse imagery or are made aware of it, we respond quickly to remove and report it to the appropriate law enforcement authorities."