Serial sex offender Dennis McKenna could be free from jail within two weeks. width=device-width, initial-scale=1, shrink-to-fit=no" name="viewport"/>One of WA’s worst paedophiles could be free in weeks. One of WA's worst serial paedophiles, Dennis McKenna, will be free within weeks after serving his sentence. One of WA’s most notorious paedophiles will likely be released back into the community in a matter of weeks, despite two of his victims’ grieving mother urging authorities to.