The Maryland state prosecutor's office is investigating two contracts awarded by Prince George's County to the chairman of County Executive Jack B. Johnson's 2006 campaign committee, according to two government sources with direct knowledge of the inquiry and two people who have appeared before a state grand jury.

Prosecutors have questioned at least two grand jury witnesses about the contracts, each for $100,000, awarded in 2003 and 2004 to Wilbert R. Wilson, owner of a Largo technology firm and Johnson's friend and neighbor for nearly 20 years, according to the sources and witnesses.

According to the contracts, each for $8,333.33 a month, not to exceed $100,000, Wilson was asked to "evaluate trends in regional, national and global economics, identify market trends and strategies for improvement of economic benefit to county-based businesses." Both contracts state that Wilson "shall furnish a final written report to the administrator in such form as may be required by the administrator."

County officials, asked on Wednesday, have not been able to provide any memorandums, report or other work produced by Wilson, who is chairman of Johnson's "Vision for 2006" campaign committee.

Wilson, 62, did not respond to a series of phone messages left in the past week seeking comment, nor did he respond to a reporter's note left on the front door of his Mitchellville home. County spokesman James Keary said Wilson is no longer under contract with the county.

Johnson yesterday declined to comment on the contract or the state investigation.

"You can go fishing, but you're not going to find anything," Johnson said. "I'm absolutely convinced Prince George's County under my administration is the most ethical, well-managed that you'll find."

The examination of Wilson's contract represents a widening of the inquiry by State Prosecutor Robert A. Rohrbaugh into the awarding of contracts in Prince George's County. In September, a grand jury indicted Robert L. Isom, former deputy director of the county's Department of Environmental Services, on charges that he demanded a $250,000 bribe from a company seeking a $1 million security contract. Isom pleaded guilty to conspiring to demand and receive a bribe.

Now there is evidence that the scope of the investigation has widened to include consulting contracts awarded by the office of the county executive.

One of the grand jury witnesses, Carolyn Scriber, former director of the county's Office of Central Services, which reviews contracts and purchasing and handles the management of county buildings and vehicles, said she testified that Wilson's 2003 contract was put through without her knowledge or review. Had she been asked, she said, she would not have signed off on it.

Under county procedures, Scriber said, all contracts are supposed to undergo administrative review before they are executed. She said the review is conducted by the county attorney and the directors of the departments of Central Services, Budget and Finance.

"I told them the contract was not one that I would have agreed to," said Scriber, who was given information about Wilson's contract by state investigators. She said the agreement was too vague.

"There was no measurement, no work product, for example, something saying at the end of six months you have to produce a report," Scriber said.

Keary said the county followed procedures in awarding Wilson's contracts. "There is nothing sinister about this," he said. "This is a legally granted contract. It followed the procedure for contracts given to experts and specialists."

Scriber headed Central Services when Wilson's first contract was awarded. Johnson fired her in May 2003 after she had served seven years in the post. She was replaced by Pamela K. Piper, a Johnson appointee. County officials offered no explanation for the dismissal, other than that Scriber, like other department heads, served at Johnson's pleasure.

Scriber said her testimony was not an attempt to retaliate. "I was subpoenaed to go to the grand jury," she said. "They didn't say I had a choice."

The first contract was signed on Feb. 13, 2003, by Jacqueline K. Brown, Johnson's chief administrative officer. The second, identical to the first, was signed on Jan. 22, 2004, by Iris B. Boswell, then a special assistant to the county executive. Both were also signed by deputy county attorney Stephanie Pratt Anderson.

Late last month, according to government sources, Brown and Boswell were subpoenaed to appear before the grand jury. Brown has yet to appear because of scheduling conflicts, but Boswell, now deputy chief administrative officer for finance, has appeared, the sources said. Several other former and current county employees have also appeared in recent months, including Floyd Wilson (no relation to Wilbert Wilson) director of the county's Minority Business Development Division.

Wilbert Wilson, a former teacher and the owner of Future-Tech Management Systems, a small technology firm in Largo, is well known in county politics. He ran unsuccessfully for County Council twice, once as a Democrat, then as a Republican. He also served as an adviser to former county executive Lawrence J. Hogan (R).

Since taking office, Johnson has shown a clear preference for hiring those with whom he has had long relationships or who worked on his 2002 campaign.

"I wouldn't hire my enemies," Johnson once said when questioned about some of his selections.

Johnson gave David Valderrama, a former state delegate who helped build support for him in southern Prince George's, a $53,000 consulting contract to monitor school construction. A similar contract, for $67,000, went to the Rev. Chet Howard, a minister at From the Heart Church Ministries, one of the county's largest churches and one that Johnson often visited in his campaign. Former council member Ronald V. Russell received $80,000 to "provide advice to the county regarding government legislative services." There is no indication that prosecutors have raised questions about these contracts.

This is the second state probe involving Johnson in the last two years. Last year, Johnson was the subject of a six-month inquiry into whether he withheld $5 million from Prince George's Hospital Center until officials hired one of his associates as a senior manager. Johnson was cleared of any wrongdoing.

Staff writer Allison Klein contributed to this article.

County Executive Jack B. Johnson, right, with council member Tony Knotts at a ceremony Wednesday, says an inquiry into contracts awarded to the manager of his reelection campaign will show no wrongdoing.