For weeks now, Syrians have nervously awaited the results of a UN investigation into the February murder of former Lebanese Prime Minister Rafik Hariri. The report, due next week, may implicate key members of Syria's Baathist regime, and on Tuesday it may have claimed its first casualty. The body of Syrian Interior Minister Ghazi Kena'an, a key witness and possible suspect in the Harriri case, was discovered in his office Wednesday morning, reportedly shot in the head. Syrian officials say he committed suicide.The UN team, lead by German prosecutor Dehtev Mehlis, startled the Syrian authorities when it showed up in Damascus last month, demanding interviews with Kena'an and other top officials. For many years, Kena'an was the head of the Syrian secret police in Lebanon, and was widely viewed as the main enforcer of the Syrian occupation of Lebanon even after he returned to Damascus last year to become interior minister.Syria has long denied any involvement in Hariri's assassination, but many Lebanese believe that the Syrians forced Hariri from power and then murdered him because the billionaire politician credited with rebuilding post-civil war Lebanon had grown too independent of his erstwhile Syrian backers.If that were true, the plan backfired, because the assassination triggered a chain of events that forced Syria to withdraw from Lebanon in May. If Kena'an was in fact involved in the assassination, his suicide would be an unusual way of saving himself and his country from disgrace: Arab culture doesn't have a tradition of dishonored bureaucrats falling on their swords.Syrian officials aren't commenting on the details of Kena'an's death, but have promised an investigation. In the meantime, Syria is running out of friends. The United States has ratcheted up pressure on the Assad regime, which it accuses of aiding the insurgency in Iraq. And other traditionally supportive Arab countries, especially Sunni-dominated Egypt and Saudi Arabia, have turned a cold shoulder. Hariri was himself a Sunni, and a Saudi citizen with close ties to the royal family.Nor is the fragile Syrian economy in a position to deal with further isolation. Despite soaring global energy prices, the country's small but critical oil industry is in decline. If the UN investigation were to result in some form of Security Council action or sanctions, the very future of the Assad regime will be open to question.