Police are investigating claims the family of a teenager who died after online bullying have received similar abusive messages.
Hannah Smith, 14, from Leicestershire was found hanged on Friday.
Her older sister Joanne Smith, 16, is understood to have received hateful taunts online.
Leicestershire Police, which is investigating Hannah's death, confirmed it was also looking into further "inappropriate postings".
It has been alleged Hannah died after bullying comments were posted on the question-and-answer site ask.fm.
On Thursday, Prime Minister David Cameron said people should boycott websites that fail to tackle online abuse.
Specsavers, Vodafone, Laura Ashley and charity Save the Children have pulled ads from ask.fm.
Opticians Specsavers said it was taking the action due to its "deep concerns" over cyber-bullying.
Hannah's father, David Smith, 45, said he had called in police for a second time to put an end to the abuse.
He said abusive messages had been left on Joanne's Facebook page and a tribute page set up in Hannah's memory.
A spokeswoman for Leicestershire Police confirmed further abuse towards the family was being investigated by officers.
She said: "We are aware that Mr Smith, Hannah's father, has contacted us regarding inappropriate postings on a Facebook page.
"They are being considered as part of an ongoing investigation."
Facebook said any comments which violated the website's terms were being removed.
In an interview with the Daily Mirror Mr Smith said: "It defies belief. We're grieving and yet people still think it's funny to send these messages.
"Me, personally, I think ask.fm, the people that run it should get done for manslaughter or murder because you try contacting them and they just don't care. They don't care that teenagers are dying and killing themselves."
Ask.fm allows users to send messages to one another anonymously, although users must register an email address, name and date of birth.
A spokeswoman for the Latvian-based website, said: "We have reached out to the Leicestershire police and would be happy to co-operate with their investigation into the true circumstances.
"Ask.fm actively encourages our users and their parents to report any incidences of bullying, either by using the in-site reporting button, or via our contact page.
"All reports are read by our team of moderators to ensure that genuine concerns are heard and acted upon immediately and we always remove content reported to us that violates our terms of service."
An inquest into Hannah's death was opened and adjourned at Leicester town hall on Tuesday.
A private funeral service is expected to take place in Leicestershire next week.