DIAMOND BAR, Calif. (AP) _ Four years ago the Republican Party saw a rising star in then-Mayor Jay Kim and urged him to run for Congress.

An immigrant who had risen from janitor to civil engineer, Kim won the seat in the solidly middle-class 41st District, becoming the first Korean-American House member.

The following year, however, investigators began looking into Kim's campaign finances, including allegations that Kim improperly used $485,000 from his engineering firm for his campaign.

No charges have been brought against Kim. But in recent months, three Korean companies have admitted to laundering contributions to Kim's 1992 campaign by funneling them through employees.

The guilty pleas could hurt Kim as he seeks a third term in California's March 26 primary. He faces just one primary opponent, securities broker Bob Kerns, who attacked Kim for not being straightforward in answering questions about the probe.

``You can never get a clear idea of what happened,'' Kerns said. The winner will face Democrat Richard Waldron, an Anaheim lawyer.

Kim, who turns 58 the day after the primary, insists he didn't know that the companies had reimbursed the personal contributions of employees.

``This happened four years ago,'' he said. ``It was brought up in the last election heavily, then it goes away, then it came back. ... There have been absolutely no charges made against me.''

Kim's political career began in 1990, when he was elected to the City Council in Diamond Bar, about 25 miles east of Los Angeles. The next year he was elected mayor and his political fortunes began to rise.

During the 1992 Republican National Convention, Kim electrified the audience with a speech about the American dream and he was elected to Congress that November.

The next year, he recorded the freshman class's only 100 percent attendance record and was named an outstanding legislator by freshmen GOP colleagues.

But midway through that year, a federal grand jury subpoenaed records from Kim's company in an investigation of his campaign finances.

That investigation took center stage in the '94 GOP primary as four opponents hit him hard on the charges. Kim struggled through the primary, then cruised to re-election in November in the heavily Republican district.

In recent months, Hyundai Motor America, Korean Airlines and Samsung America Inc. have agreed to pay fines totaling $1 million for breaking U.S. election laws that bar corporations and foreign nationals from contributing money to federal candidates. It also is illegal to make contributions under someone else's name.

In January, a newspaper published a confidential 1995 memo from Kim's lawyer to Kim, saying the federal investigation was focusing on destruction of evidence and obstruction of justice. Kim said the memo was stolen from his office desk and demanded an investigation of the alleged theft.

Last week, Hyundai Motor America controller Paul Koh was charged with conspiracy to defraud the government in the illegal Hyundai contribution. Trial was set for May 14.

And in the latest setback, an FBI agent said in court documents that two witnesses in the federal probe of Kim have been threatened or harassed by unspecified people.

Stanley W. Moore, a professor at Pepperdine University, said he doesn't think the indictments and convictions will hurt Kim's re-election bid. John Petrocik, a UCLA political scientist, disagrees.

``If campaign money is somehow attached to an illegal operation, I would imagine you'd get hurt by it in direct proportion to the ability of your opponent to make it an issue in the campaign,'' he said.

Reaction was mixed among Diamond Bar residents who live down the hill from the gated community where Kim lives in a million-dollar home with his wife, June, and three children.

``He's doing his best,'' said Young Kang, who works at a dry cleaner. ``I hope he's re-elected. Of course he's a minority, he's Korean-American, Asian-American _ but also his abilities are good.'

Jim MacInnis, who runs a flower shop, said he hasn't decided whom he'll vote for _ but it won't be Kim. MacInnis said Kim's campaign workers wrote bad checks to his shop in 1992, and added that Kim has been a lackluster lawmaker.

``He hasn't done anything that I've seen,'' MacInnis said.