The chief constable of Greater Manchester Police, Michael Todd, has been found dead. Sky sources say his car was found in Llanberis, North Wales.
Deputy chief constable David Whatton said Todd had gone missing while off-duty and walking in Snowdonia on Monday.
"Last night we became concerned for his welfare and as a result searches started to find him," Whatton said.
"Unfortunately, this afternoon a body has been found."
"I believe it is Michael but we have not been able to formally identify him at this time."
"The weather conditions are extremely bad at the moment and are hindering our inquiries."
"There will be a coroner's investigation which means I can't say any more at this time."
"As you can imagine all of his friends and colleagues are extremely upset. Our hearts and thought are with his family, and I would ask that they be left in peace to come to terms with this tragic shock."
Sources said suicide was one line of inquiry. It is understood that Todd faced personal problems.
His body was found at the bottom of a cliff on Snowdon.
Ian Henderson, secretary of Llanberis Mountain Rescue Team, said the operation to retrieve Todd's body was ongoing.
He said the body was discovered high up Snowdon near Bwlch Glas.
Mr Henderson said: "We have a team on there working on the recovery of the body. We anticipate it will be another couple of hours before we get him down from the hill."
The rescue operation involves not only Llanberis Mountain Rescue but the RAF and Ogwen Valley Mountain Rescue team which was called today at 2:30 p.m. to assist in the search.
An RAF spokesman said a helicopter from RAF Valley in North Wales was scrambled and it could be 8 p.m. before the body is removed.
Home Secretary Jacqui Smith said: "I have been saddened to learn that Greater Manchester Police colleagues believe that Chief Constable Michael Todd has died.
"Chief Constable Todd has had a long and distinguished career in various forces and has contributed greatly to the fight against crime and terrorism."
"My thoughts are with his family, friends and colleagues."
Mr Todd lived in a flat in Manchester city centre but his family home was in Nottinghamshire, according to a police spokesman.
He is believed to have at least two children.
Sky's crime correspondent Martin Brunt said Todd was tipped as a possible future commissioner of the Metropolitan Police in London.
"Some chief constables keep a low profile, but Mike Todd was one of those who enjoyed joining with media and using the media to get his message across," said Brunt.
"Even after he'd left the Met police and he was in Manchester he would always come over when he saw me and have a chat. There aren't many police chiefs like that."