The federal government is investigating the takeover last year of a leading American manufacturer of electronic voting systems by a small software company that has been linked to the leftist Venezuelan government of President Hugo Chvez. The inquiry is focusing on the Venezuelan owners of the software company, the Smartmatic Corporation...and its subsidiary, Sequoia Voting Systems of Oakland, Calif.. Smartmatic was a little-known firm with no experience in voting technology before it was chosen by the Venezuelan authorities to replace the country's elections machinery ahead of a contentious referendum that confirmed Mr. Chvez as president in August 2004. With a windfall of some $120 million from its first three contracts with Venezuela, Smartmatic then bought the much larger and more established Sequoia Voting Systems, which now has voting equipment installed in 17 states and the District of Columbia. The concern over Smartmatic's purchase of Sequoia comes amid rising unease about the security of touch-screen voting machines and other electronic elections systems. The concerns about possible ties between the owners of Smartmatic and the Chvez government have been well known to United States foreign-policy officials since before the 2004 recall election in which Mr. Chvez...won by an official margin of nearly 20 percent. But after a municipal primary election in Chicago in March, Sequoia voting machines were blamed for a series of delays and irregularities. Smartmatic's new president, Jack A. Blaine, acknowledged in a public hearing that Smartmatic workers had been flown up from Venezuela to help with the vote.