PHILADELPHIA (AP) — An architect involved in a fatal building demolition in Philadelphia is refusing to turn over documents sought by the Department of Labor.

A lawyer for Plato Marinakos cites his client’s Fifth Amendment right against self-incrimination, saying he “reasonably” fears a pending grand jury investigation.

READ MORE: 2 Suspects In Custody After Shooting Near Lincoln High School Left Man Killed, 16-Year-Old In Critical Condition, Police Say

The June 5th collapse of a towering brick wall being demolished killed six people at an adjacent thrift store.

Marinakos is due in federal court Wednesday over his stalemate with the Occupational Safety and Health Administration.

The OSHA subpoena seeks demolition and safety plans, photographs and correspondence with demolition contractor Griffin Campbell.

READ MORE: John Dougherty, Bobby Henon Corruption Trial Resumes Tuesday

Marinakos has turned over 116 pages of material, but says the rest is protected.

Demolition subcontractor Sean Benschop is charged with six counts of involuntary manslaughter. Several civil lawsuits have also been filed.

(© Copyright 2013 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)

MORE NEWS: Hit-And-Run In Pennsauken Township, New Jersey Leaves Man Dead