Two former Prince George's County officials, under investigation by the Maryland state prosecutor's office for allegedly receiving bribes, allegedly sought $250,000 in exchange for awarding a $1 million security contract, according to three government officials with direct knowledge of the investigation.

The two former officials, Robert L. Thomas and Robert L. Isom, have not been charged with a crime. Agents for the state prosecutor executed search warrants last month at their homes and county offices, seizing records and computer equipment.

Isom, who was deputy director of the county's Department of Environmental Resources, was fired May 24 after county officials received affidavits from the prosecutor's office outlining the information compiled by investigators. Thomas resigned several weeks ago as deputy director of the Office of Central Services, which handles county contracts, purchasing and the management of county buildings and vehicles.

The three government officials said the money was to be paid by a subcontractor -- officials will not name the company or the prime contractor -- in installments of several thousand dollars. Isom and Thomas allegedly took at least one payment while the firm was cooperating with state investigators, the officials said.

The contract involved work to upgrade security at the county administration building.

Investigators also have searched a Largo tax consulting business, J.R. Thomas & Associates, run by Thomas and his wife, Juanita, and an Upper Marlboro accounting company owned by Paul L. Wright. Neither Wright nor Juanita Thomas is accused of wrongdoing.

The money from the subcontractor was to be laundered allegedly through the accounting and tax businesses, the government officials said.

Neither Thomas nor Wright returned repeated phone messages left at their homes.

Charles Maddox, Isom's attorney and a friend of more than 30 years, declined to comment. Isom worked as a deputy inspector when Maddox was the District's inspector general. Maddox resigned in 2003 after the D.C Council raised questions about his performance.

Isom, 67, who left his District job in 2002, was one of the Environmental Resources Department's four deputy directors for 11 months. He said last week that he was stunned when investigators showed up at his front door.

One minute he was shaving, he said, getting ready to head to work. The next, he said, he was reading an affidavit and watching agents rifle through his Upper Marlboro home.

"This has really upset me," Isom said last week. "I didn't do anything wrong."

Thomas, 40, also worked in District government, joining the Office of Tax and Revenue in 1996 after working in criminal investigations for the Internal Revenue Service. From there, he moved to the inspector general's office, where he oversaw investigations.

In April 1997, then-Mayor Marion Barry appointed Thomas interim inspector general. Six months later, Barry nominated him for the permanent position.

Thomas never got the job. The financial control board rejected him, largely because of his decision to hire Mitchell Titus & Co., a D.C. accounting firm, to perform the city's annual financial audit. A member of Mitchell Titus was one of Thomas's original references for the job at the inspector general's office.

He went to work for Prince George's in June 2003 as a consultant to the Office of Central Services, receiving $11,400 a month, for five months, to analyze the office's budget, assess accounting practices and provide financial planning. A month after his contract expired, County Executive Jack B. Johnson (D) hired him as a deputy director in the agency, at an annual salary of $103,530.

The government officials said Thomas later recommended Isom for his $95,303 deputy director's job at Environmental Resources.

Thomas lives in Port Tobacco in a house bought in his wife's name in July for $481,484.

Court records show that Isom filed for bankruptcy in 1995 under Chapter 7, a personal liquidation of assets, and listed more than $200,000 in liabilities. The case was discharged. He has twice refinanced the home he and his wife have lived in since 1973, once in 1998 for $142,500 and again in June 2003 for $155,500, according to public records.

Vernon Herron, county's public safety director, said last week that neither man has a personal relationship with the county executive. In recent months, Johnson has come under scrutiny for filling many deputy director positions with friends and supporters.

"We did a full background check, and there was nothing that raised a red flag," Herron said.

Staff researcher Bobbye Pratt contributed to this article.