The investigation into historic sex offences against Sir Cliff Richard has expanded and now includes more than one allegation, South Yorkshire Police (SYP) have said.
Richard, 74, was questioned, but not arrested, last year over allegations he sexually assaulted a boy under the age of 16 at a religious rally in Sheffield in 1985.
South Yorkshire's chief constable David Crompton said the investigation into the veteran singer has now "increased significantly in size" since his home was first raided by officers last August.
Crompton said he has written letter to Keith Vaz, chairman of the Commons Home Affairs Select Committee, to say he could not give a definite date when the investigation would be concluded, but the force is in regular contact with Richard.
"This is an investigation which has increased significantly in size since its inception. Sir Cliff Richard's lawyers are aware that there is more than one allegation," Crompton said.
He added: "It would be premature and potentially misleading to predict a likely date when it will be concluded, however, we are progressing as swiftly as possible."
Richard has denied the allegations against him and has vowed to clear his name.
He added: "I have no idea where these absurd and untrue allegations come from. The police have not disclosed details to me. I have never, in my life, assaulted anyone and I remain confident that the truth will prevail.
"I have cooperated fully with the police, and will, of course, continue to do so. Beyond stating that the allegations are completely false, it would not be appropriate for me to say anything further until the investigation has concluded, which I hope will be very soon.
"In the meantime, I would, again, like to thank everyone for supporting me through this unbelievably difficult period."
The BBC and SYP were recently criticised for causing "unnecessary distress" to Richard after they set up a camera crew to film police entering his Berkshire home following a tip-off.
Former chief constable Andy Trotter said the incident caused "considerable cost" to the reputation of the force.
A Crown Prosecution Service (CPS) spokesperson said: "The CPS is providing early investigative advice in relation to allegations of sexual offences committed by a 74-year-old man, interviewed by police in August 2014.
"The allegations remain under investigation by South Yorkshire Police."