Police in Lancashire are hunting a man from Chorley who posted "sick" comments about missing schoolgirl April Jones online.
His comments sparked an angry backlash on Facebook.
A vigilante group is reported to have called at the man's parents' house in Chorley.
Lancashire Police confirmed it was investigating the comments and was looking for a man in connection with their inquiry.
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Serial offender Barry Dyson 39, hid the mirror in his rucksack and took it out to prey on women as they shopped in a city centre store.