Andre J. Hornsby traveled about 1,300 miles to speak here at the National Alliance of Black School Educators convention, but all around him were reminders of an ethics controversy he temporarily left behind in Prince George's County.

Two of the sponsors are Plato Learning and LeapFrog SchoolHouse, educational software companies that paid undisclosed amounts for their convention sponsorships. As the Prince George's schools chief spoke on a panel Wednesday, Plato and LeapFrog SchoolHouse representatives were among vendors setting up exhibits to tap into what the convention's Web site called "the purchasing power and influence of the largest concentration of African American educators" in the nation.

Back in Maryland, several agencies, including the FBI and the Prince George's school board's ethics panel, are investigating Hornsby after questions were raised about his dealings with the two companies.

In July 2003, Hornsby accepted a scholarship from Plato that covered the expenses of a 10-day trip he took to South Africa when he was president of the alliance. Hornsby had been hired a month earlier by the Prince George's school board, and he disclosed the trip but not that it was paid for by Plato, a Minnesota company that does business with the school system, according to board Chairman Beatrice P. Tignor.

Under scrutiny, too, is whether Hornsby should have disclosed before the school system decided to purchase nearly $1 million of software and other teaching tools from LeapFrog SchoolHouse that he lives with a Virginia saleswoman for the California-based company.

The goal of the alliance, a nonprofit organization with nearly 7,000 members, is one few would argue against: to encourage black educators to become leaders in school districts across the country.

Charles Moody, the group's founder, said the alliance plays an important role in nurturing African American leaders. When he started the group in 1970, there were 22 black school superintendents across the country, he said. Now there are about 350, according to Moody.

But with the federal No Child Left Behind Act encouraging schools to spend public dollars on private solutions to low test scores, vendors are marketing their products more aggressively at conventions such as the alliance's annual meeting. Experts and business ethicists say it has become too easy to cross the line, or give the appearance of crossing the line, as vendors entertain school officials with purchasing power.

Hornsby's critics say they don't begrudge him the right to attend professional conferences, but they worry about his proximity to vendors when he is being investigated about questionable associations.

"I would just hope the lessons learned in Prince George's County the last few months about keeping a distance from private companies and contractors currying favor is something he takes with him," said Maryland state Sen. Paul G. Pinsky (D-Prince George's).

The alliance's gathering is by no means the only education convention that brings together vendors and school officials. Companies selling computer software, consulting services, even classroom furnishings are regular sights at conferences organized by the American Association of School Administrators, the National Association of Secondary School Principals and the National Association of Elementary School Principals, to name a few. Among the sponsors of the National Alliance of Black School Educators convention is Kaplan Inc., which is owned by The Washington Post Co.

Hornsby, 51, has been a member of the alliance for more than half of the 34 years it has been in existence. He has been a regular at its annual convention for 19 years and was the group's president from November 2001 to November 2003. He still holds a seat on its board of directors.

Hornsby has said he did business with Plato and LeapFrog SchoolHouse because of the quality of their products, not because of personal relationships. At the convention, his talk focused on the relationship between superintendents and school boards. "My board does hold me accountable," he said, "you can rest assured of that. But there's trust there, and I believe in giving as much information as possible."