Arlington public works officials said yesterday they halted unauthorized expansion of a parking lot in Crystal City operated by the giant parking corporation, Parking Management Inc. (PMI), several hours after work began.

It was the second time this year that Virginia officials have questioned PMI operations in Arlington. In April, Virginia highway officials discovered that PMI had, without permission, opened a parking lot on state-owned land planned for a highway project.

Public works inspector Frank Johnson said, the construction was discovered Thursday morning when a resident of a high-rise apartment complex across the street from the lot on South Eads Street noticed that a five-man crew was clearing brush and loading it on red, white and blue trucks owned by Excavation Construction Inc.

The resident, who asked not to be identified, called the county Public Works Department to inquire why the trees and bushes adjacent to a 150-space parking lot were being cut down.

When county officials said they did not know, inspector Johnson visited the site near the Crystal City Metro station. Johnson said that when he arrived, shortly before 9:30 a.m. he asked the crew leader whether he had a permit to enlarge the lot.

"I told them they had 20 minutes to call their office and get the permit number and I'd be back, because I had to check out another site," Johnson said. "When I got back 20 minutes later the place was locked up and everyone was gone."

County public works director Henry S. Hulme Jr. said that 10 expand the parking lot PMI officials receive a building permit after submitting engineering sketches detailing drainage and curbing. Under routine conditions, Hulme said, a permit could be issued within a few weeks.

Hulme said that to his knowledge PMI had not applied for a building permit.

PMI officials, including John Lyon, the firm's general manager who is also president of Excavation Construction, did not return a reporter's phone calls yesterday.

Excavation Construction, a multimillion-dollar firm headquartered in Prince George's County, is under investigation by federal grand juries in Baltimore and Washington. The Maryland probe centers on allegations that the construction firm and other large business concerns were involved in racketeering with former Teamster Union bosses in Baltimore and Washington.

The federal grand jury in the District of Columbia is exploring allegations that D.C. Superior Court Judge Robert H. Campbell suspended or revoked fines for the construction firm.