The two men, aged 51 and 56 and both from Burnley, were detained shortly after 7pm this evening.
Both were arrested on suspicion of two counts of murder, two of rape and one of arson with intent to endanger life. Both remain in police custody.
It comes after detectives issued a plea for information following the discovery of two bodies at a house in Reedley.
Police were initially called at around 8-45am on Thursday to a report of concern for the safety of the occupants of an address in Colne Road.
When officers attended they found the bodies of two females, as well as evidence of smoke and fire damage inside the address.
One of the victims has since been formally identified as Dr Saman Mir Sacharvi, aged 49. The body of the girl has yet to formally identified but is believed to be Dr Sacharvi’s daughter, 14-year-old Vian Mangrio, who was a pupil at Marsden Heights School in Nelson. The two lived together at the address.
A Home Office post-mortem yesterday revealed Dr Sacharvi died as a result of pressure to the neck. She had also suffered an assault.
Although the post-mortem investigation remains ongoing for Miss Mangrio, so police cannot give a cause of death, they can confirm she was found badly burnt inside the address.
Dr Sacharvi and Miss Mangrio’s next of kin are being supported by specially trained offices.
Det Supt Jon Holmes, Head of Major Crime at Lancashire Police, said: “We are on with a number of lines of enquiry and this evening we have made two arrests.
“However this is a live investigation and we continue to ask anyone with any information to get in touch with us.
"Perhaps you have been in the Colne Road area recently and have seen something suspicious. Maybe you have CCTV or dashcam footage which could contain something useful. Or perhaps you think you know who is responsible. Whatever information you have, we would urge you to get in touch, even if you think what you know is insignificant.
“Finally our thoughts remains with Dr Sacharvi and Miss Mangrio’s family and friends at this awful time and we send them our deepest condolences. We have a team of detectives dedicated to the investigation and we will leave no stone unturned.”
Anyone with information is asked to contact police as soon as possible through the dedicated Major Incident Portal at https://mipp.police.uk/operation/0401020119P01-PO1 or on 101, quoting log 0429 of October 3rd.
Alternatively independent charity Crimestoppers can be reached anonymously on 0800 555 111 or at crimestoppers-uk.org.