Police have confirmed that the Leicester fire in which four members of the same family died is being treated as a murder investigation.
A woman in her 40s, Shehnila Taufiq, died along with her daughter Zainab and two sons, Jamal and Bilal, in the fire at the house in the Wood Hill area of the city.
The children's father, Dr Muhammad Taufiq al-Sattar, works as a neurosurgeon at Beaumont Hospital in Dublin. It is believed that he is returning to Leicester.
The bodies were discovered in an upstairs bedroom. Police said they were treating the deaths as murder and have not ruled out there could be a link between them and the murder of a man in his 20s in the city centre earlier that evening.
Police said they are looking into whether the fire could have been started out of revenge. The proximity and the length of time between the two "terrible, terrible crimes" pointed to a link, they said.
A murder investigation had been launched after the fatal assault in Kent Street. He was taken to the Leicester Royal Infirmary but died from his injuries.
Assistant Chief Const Roger Bannister said: "These are obviously both very serious incidents and investigations have begun to establish if there are any links between them.
"I can't confirm here and now it is a revenge attack - it may be, it may not be - but lines of inquiry will certainly get to the bottom of that.
"We are working closely with the fire brigade. [to figure out] exactly how the fire started, where it started and who is responsible."
DCI Simon Cure, who is leading the enquiry, said: "Our investigation is in its very early stages and we are carrying out a number of enquiries to try to establish what has happened."
Officials at the Leicester mosque attended by the Taufiq family said they were "extremely shocked" by the deaths.