The feds are digging deeper into Detroit's blight removal program involving millions of dollars in federal money spent in tearing down homes.
The city will be forced to hand over records from January of 2014 when Mayor Mike Duggan took office.
More than 8,000 homes have been demolished in the past two years but with skyrocketing costs.
Charlie LeDuff has done extensive reports on the story and explained what federal investigators are after and gives his opinion.
"The feds are looking for everything," LeDuff said. "After we did our report, Detroit City Council President Brenda Jones asked for an audit of the city. That's inside city hall. The feds want to get their hands on this stuff before it disappears.
"According to the auditors general's report and the subpoena. This is very convoluted, undocumented relationships between city departments and hard to figure out.
"(They are looking for) what's the validity of contracts; who is meeting with whom; who got special treatment; on and on. Stuff we have been living through, a nightmare in the city for eight years."
LeDuff's initial investigation was that demolition costs had skyrocketed and doubled in some cases - even after the feds gave the city $177 million.
Watch the video above to see LeDuff talk about contractors, bids and meetings held by Mayor Duggan.
For previous reports by the Americans with Charlie LeDuff on the Detroit’s demolition:
Is Detroit's demolition math fuzzy?
Duggan defends Detroit's skyrocketing house demo cost
Demo disaster: Detroit’s secret negotiations with contractors
Detroit’s demo disaster: Blame it on the dirt
Detroit’s demo disaster: A Land Bank Peyton’s Place?