The shocking incidents have been mentioned in a report by the respected Physicians for Human Rights group into war crimes and atrocities in the embattled city, which faced two months of being cut off from the rest of Libya.
The report has suggested that the father carried out the 'honour killings' after facing humiliation and shame over the rape of his 15, 17 and 18 year-old daughters in Tomina, on the outskirts of Misrata. The victims were not named, the Daily Mail reports.
This incident is just one among series crimes carried out on civilians by Gaddafi's troops.
The human rights group, which is based in Boston has concluded that there was widespread evidence of war crimes during the siege.
"Four eyewitnesses reported that (Gaddafi) troops forcibly detained 107 civilians and used them as human shields to guard military munitions from Nato attacks south of Misrata," the report said.
A huge controversy emerged earlier this year after a woman named Al-Obeidi claimed that she was raped by Gaddafi's men. She had later moved to the US.
Reports had also emerged that Gaddafi troops and loyalists were issued Viagra-type drugs to sustain their systematic rape campaign.