Three people are being questioned by detectives investigating a murder possibly linked to a fatal house fire which killed a mother and her three children.
Shehnila Taufiq, who was in her 40s, died along with her 19-year-old daughter and sons, aged 17 and 15, in the blaze at their home in Leicester in the early hours of yesterday The mother and her children, named by their local mosque as Zainab, Jamal and Bilal, died in their bedrooms at their terraced house in Wood Hill in the Spinney Hills area of the city, several hours after a man was killed in nearby Kent Street.
Police believe the family may have been killed in a revenge attack, which neighbours claimed could have have been a case of mistaken identity.
A man and two women, all aged 19, were arrested over the killing of the man in his 20s - named in reports as father-of-one Antoin Akpom. Police said the man was arrested in London.
Mrs Taufiq's neurosurgeon husband, Dr Muhammad Taufiq Al Sattar, was yesterday believed to be on his way home from Ireland, where he works.
Police have said they cannot rule out a link between the two events and they are investigating whether the fire was started intentionally as a revenge attack.
Neighbours of the family reacted with disbelief to the idea that they could have been intentionally killed - and claimed they may not have been the intended target.
A middle-aged man, who did not want to be named, said: "Most people feel this was meant for somebody else and they got the wrong house." Leicestershire Police has not yet confirmed the identities of the five victims.
The force launched its first murder inquiry shortly after 5.30pm on Thursday when a man in his 20s was taken from Kent Street - half a mile away from the scene of the fire - to Leicester Royal Infirmary, where he died.
A second inquiry began when neighbours reported flames shooting out of the first floor of the Taufiq family home at 12.30am.
Assistant Chief Constable Roger Bannister said officers were investigating a theory that Mrs Taufiq and her children were killed in revenge for the earlier attack.
He said: "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." Urging witnesses to get in touch, he said it was possible that both offences, which he described as "terrible, terrible crimes", were linked.
Mr Sattar is a consultant neurosurgeon and has been working in Beaumont Hospital in Dublin and with private hospitals in the city, the Blackrock and Hermitage clinics.
It is understood Mr Sattar's wife was a qualified doctor but was not working.
The family is originally from Pakistan and had a home in Ireland for at least 15 years. They were together about a month ago spending the festival of Ramadan in Ireland.
The children moved to the UK with their mother about five years ago for Islamic education which is not available in Ireland but returned regularly to be with their father at the family home in the Castleknock area of the Irish capital.
Dr Ali Saleem, of the Islamic Cultural Centre in Dublin, said the family planned to reunite in Ireland after the children finished their education.
Police said the victim of the Kent Street murder had not yet been formally identified.
Forensic examination of the fire scene and the surrounding street is under way.
Police said in a statement: "The whole area is being carefully examined which may take some time. Specially-trained officers will be searching for evidence connected to the incident and this requires careful searching under and around vehicles parked in the street, front gardens and pavements.
Detectives would like to thank the residents of Wood Hill for their patience and co-operation while this is ongoing."
- Matthew Cooper, John Fahey and Ed Carty, Press Association