The sentences of two men jailed after the murder of Bijan Ebrahimi in Bristol will not be referred to the Court of Appeal, the Attorney General has said.
A disability rights group had written to Dominic Grieve saying the sentences were "lamentably light".
Mr Ebrahimi was beaten to death before his body was set on fire.
Lee James was jailed for life for murder with a minimum term of 18 years, Stephen Norley for four years after he admitting assisting burning the body.
The Disability Hate Crime Network said James could have got at least 30 years if the judge decided hostility towards Mr Ebrahimi's disability was a factor. Mr Ebrahimi had also been falsely accused of being a paedophile.
"This was a missed opportunity to send a very strong message out to people who wrongly accuse disabled people of paedophilia," Katharine Quarmby from the charity said after sentencing.
But a spokesman for the Attorney General said he had decided not to refer the sentences as he did not think the Court of Appeal would increase them.
"A sentence will only be unduly lenient if it falls significantly below the sentence that any judge could reasonably have imposed. That is a very high threshold," the spokesman said.
"Even then, the Court of Appeal has a wide discretion as to whether it should actually increase a sentence in a case.
"The Attorney took all matters into consideration including, as he always does, the impact on the victim's family.
"The Attorney has written to Mr Ebrahimi's family explaining his decision and continues to offer them his deepest sympathy for this tragic case."
'Not hate crime'
The Attorney and Solicitor Generals made the decision after considering case papers from the Crown Prosecution Service (CPS) and the views of senior advocates who specialise in sentencing.
The CPS found that, despite the unpleasant bullying of the victim, there was no evidence of hatred motivated by his disability and therefore did not treat this case as a hate crime.
It also found no evidence James and Norley were motivated by hostility towards Mr Ebrahimi's race or disability when the offence was committed.