A man who posted abusive messages on memorial websites dedicated to dead children was jailed for 18 weeks and banned from using social networking sites for five years.
Sean Duffy, 25, admitted posting images on Facebook and YouTube mocking the deaths of four children, including Natasha MacBryde, 15, who committed suicide and was found dead on a railway line near her home in Worcestershire in February.
Reading Magistrates' Court heard that after her death, Duffy posted a video with Natasha's face imposed on Thomas the Tank Engine to a Facebook tribute page set up by her brother. He posted comments including, "I fell asleep on the track lolz."
Her father, Andrew MacBryde, told the court Duffy's actions had "added to the horror of dealing with the death of [their] beautiful daughter".
Duffy, who had posted the images using false details, was traced by police through information from his internet service provider and arrested.
He admitted to "trolling", a term used to describe the trend of anonymously seeking to provoke outrage by posting insults and abuse online. He pleaded guilty to two counts of sending malicious communications.
The court heard Duffy posted pictures on Facebook of car-crash victim Hayley Bates, 16, of Stoke-on-Trent, who died last September. One image showed her with crosses on her eyes and red marks on her face. A caption under a picture of flowers at the crash site read: "Used car for sale, one useless owner."
Duffy posted on an online memorial page to Lauren Drew, 14, who died after suffering an epileptic seizure at her home in Gloucestershire in January.
Posted on Mother's Day, it read: "Help me mummy, it's hot in hell." The court was told a friend of Lauren's had attempted a drug overdose after wrongly being blamed for the post. Lauren's father, Mark Drew, said: "Lauren didn't deserve this. Seeing him in court was really hard. I was so angry. This person hid behind the computer screen with no feeling."
Duffy also targeted 14-year-old Jordan Coope of Newcastle upon Tyne, who was stabbed to death. Duffy created a group called "Jordan Cooper in pieces" and made a YouTube video with pictures of Jordan's eyes crossed out and slashes across his face.
Lance Whiteford said in mitigation that Duffy had been diagnosed with Asperger's syndrome at an early age. He said one of the characteristics was an inability to judge the reaction of others. Duffy had struggled with alcohol problems and lived "a miserable existence", Whitford said.
As well as the jail sentence, Duffy got a five-year anti-social behaviour order which bans him from social networking sites and prevents him buying devices which allow him access to the net without police permission.
Anti-bullying charity Beatbullying called the conviction "a monumental move towards bullying and cyberbullying being taken more seriously". Spokeswoman Sherry Adhami said the sentence "sends a strong message ... that bullying, whether online or offline, is not going to be tolerated". A Facebook spokesman said: "It's against Facebook's rules to intimidate or harass others, and we provide everyone with the tools to report such content."