The Independent Police Complaints Commission are investigating after one man died and another needed hospital treatment as police made arrests at the house.
West Yorkshire Police officers were at Grasmere Court in Wortley, Leeds at around 7pm yesterday making a pre-planned arrest.
A 34-year-old man, who was arrested on suspicion of criminal damage, suffered what police called a "medical episode" and he was taken to Leeds General Infirmary.
He is now back in custody.
Around the same time, a 54-year-old man, who was at the house, collapsed. He was taken to hospital, where he died.
West Yorkshire Police reported the circumstances to the IPCC.
"The allegations made against two other Police Forces and the material we have found in connection with the Stephen Lawrence Inquiry raise significant issues of not just public confidence and trust, but also public interest.
"In the interests of openness and transparency I have today referred this matter to the IPCC so that an independent body can assess these matters so that the public can have full confidence in any outcome. West Yorkshire Police will co-operate fully with the IPCC and assist in any way we can to get to the truth".
Police and Crime Commissioner Mark Burns-Williamson has released the following statement about Sir Norman Bettison.
"I have become aware of three documents following a thorough search requested by West Yorkshire Police Chief Constable Mark Gilmore. These documents raise significant concerns over the role of Sir Norman Bettison at the time he was Assistant Chief Constable of West Yorkshire Police in 1998 in commissioning a report to be prepared in the respect of a key witness appearing before the Macpherson Inquiry.
"This may suggest an attempt to intervene in the course of a public inquiry and influence the manner in which the testimony of a witness, who was due to present evidence before it, was received. I have today referred this to the Independent Police Complaints Commission.
"This is a matter which needs to be thoroughly investigated, and if wrongdoing is demonstrated those responsible must face the consequences of their actions.
"Doreen Lawrence and her family need their treatment by the police service reviewed independently and this must be done as a matter of urgency.
"I am sure the IPCC will do the same for these separate issues of concern indicating possible corrupt practices around the Macpherson Inquiry. I am now seeking an urgent meeting with the Home Secretary.
"Wider issues of any institutional racism in the police service may need to be tackled with a standalone inquiry but my referral today is to make sure we understand the truth regarding the conduct of Sir Norman Bettison. I welcome the Chief Constable of West Yorkshire rightly and swiftly recognising the seriousness of this issue and dealing with it in an open and transparent way. "
Police and Crime Commissioner Mark Burns-Williamson says West Yorkshire Police have found documents which raise concerns into Sir Norman's role at the time he was Assistant Chief Constable of the force in 1998.
A report was commissioned into the background of a key witness due to appear before the inquiry when it sat in Bradford.
It comes after recent allegations that police officers tried to smear the family of race murder victim Stephen Lawrence prompting the Home Office ask police forces to review their involvement with the enquiry. Sir Norman's solicitor told ITV that he would not be commenting on the referral.
The former Chief Constable of West Yorkshire, Sir Norman Bettison, has been referred to the Independent Police Complaints Commission.
It is part of an investigation into a suggestion that he may have tried to influence the way the testimony of a witness who was due to give evidence to the Stephen Lawrence Enquiry was received.
The Independent Police Complaints Comission has asked North Yorkshire Police to investigate if any of their officers could face potential misconduct charges over their relationship with disgraced TV presenter Jimmy Savile.
The shamed DJ is said to have abused at least eight victims in the county, where he had a home in Scarborough. The IPCC has asked the force to review whether there were "conduct matters that should be referred" to them in relation to Savile.
Independent Police Complaints Commission's Deputy Chair Deborah Glass said the Hillsborough announcements were "welcome news", but added:
This is not going to be quick and easy process.
But we now have a clear path ahead with all the investigative and prosecutorial bodies working in a coordinated way to complete the full picture for the families of those who died, those who were injured and those who were traumatised by the terrible events at Hillsborough.
More than 2400 police officers could face investigation over the Hillsborough disaster, the police watchdog has confirmed. Up to 1000 additional officers may be added to the 1444 members of South Yorkshire Police already being investigated, the Independent Police Complaints Commission (IPCC) said.
The new figure was revealed as senior IPCC figures appeared before the Home Affairs Select Committee today.
It includes officers from around 20 other forces who were present when 96 Liverpool fans died during an FA Cup semi-final in 1989.
A fundraising single for the Hillsborough Disaster families is to take on The X Factor in the race for the Christmas number one. The musicians involved include Sheffield's Richard Hawley, The Clash's Mick Jones and Sixties star Gerry Marsden.
Robbie Williams's former song-writing partner Guy Chambers is to produce the single, a new version of The Hollies' hit He Ain't Heavy, He's My Brother. It will be released on December 17 with the aim of hitting number one in time for the festive season.
Proceeds from the single will go towards the Hillsborough families' legal costs in their fight for justice. It comes in the wake of a damning report into the handling of the deaths of 96 Liverpool fans who died as a result of a crowd crush at Hillsborough Stadium in 1989.
He had become a focus of increasing anger after allegations that he'd led a police cover-up to to blame fans for the Hillsborough disaster.
Today came perhaps the inevitable. West Yorkshire's Chief Constable Sir Norman Bettison resigned - before the decision was taken out of his hands and into his bosses'.
But Sir Norman went down fighting - still denying that he did anything wrong in the aftermath of the tragedy 23 years ago, when he was a Chief Inspector with the South Yorkshire force.
Relatives of those who died say he should have gone long ago. David Hirst reports.