STOCKHOLM, Sweden (AP) _ Ten years ago, an assassin killed Sweden's prime minister, Olof Palme, and escaped into the night. The nation has been in pursuit ever since.

On the 10th anniversary Wednesday night, Swedes laid flowers at the murder site and reflected on what some call their lost innocence from the still-unsolved assassination. Palme was murdered at 11:23 p.m. on Feb. 28, 1986, while he and his wife Lisbeth walked home unguarded from a movie theater.

``Something was lost in Sweden,'' said Klas Lionell, 33, wiping tears from his eyes. ``The belief that the prime minister could walk without security guards down the street, like anybody else. That has been lost.''

He stood in the winter wind in a small crowd at the spot where Palme fell along a downtown thoroughfare. An array of red roses and carnations, surrounded by candles, covered the bronze plaque cemented into the sidewalk bearing Palme's name.

Failure to nail a killer has spawned a cottage industry in conspiracy theories blaming everybody from Kurdish militants to right-wing Swedish police officers.

Some wonder whether Palme's crusades _ opposing the Vietnam War, apartheid and the arms race, and championing the welfare state, the Palestine Liberation Organization, Cuban leader Fidel Castro and Nelson Mandela of South Africa _ still have relevance.

``No,'' his onetime confidant Harry Schein has said. ``We are in a totally different political situation than we were during Olof Palme's time. ... He was a great politician, for his time.''

Palme was prime minister twice, in 1969-1974 and 1982-1986. He was a charismatic, powerful speaker who focused on statesmanship.

``I have nothing but praise for the late prime minister,'' South African President Nelson Mandela told Swedish radio from Johannesburg. ``We lost a very good friend.''

He remains controversial. Swedish radio reported Wednesday that Palme's grave has been vandalized several times during the last decade.

About a dozen detectives _ soon to be reduced to two or three _ still work full-time on the murder case, weeding out the last tips from an estimated 17,000 investigated over the years.

They haven't even found the murder weapon.

``You have to be realistic after 10 years,'' the chief detective, Hans Olvebro, said about plans to scale back the investigation.

In 1989, a petty criminal named Christer Pettersson, then 41, was tried based largely on the testimony of Palme's widow, who identified him from a line-up. But a court acquitted the man, calling the evidence circumstantial.

Since then, few hard leads have emerged. The government last year started an investigation of the investigation, which has cost about $44 million so far.

In a Gallup poll of 1,000 Swedes in mid-January, 85 percent said they believe the culprit never will be convicted, and 52 percent said the case should be closed. No margin of error was given.