The Manhattan district attorney, Robert Morgenthau, is launching a criminal investigation into the deaths of two firefighters in Saturday’s fire at the former Deutsche Bank building across the street from ground zero.

Manhattan prosecutors will join the fire department and, reportedly, the state attorney general, Andrew Cuomo, in probing the circumstances of a fire that consumed five of the abandoned building’s upper floors.

The chairman of the Lower Manhattan Development Corporation, which owns the building, Avi Schick, suggested yesterday that the contractor dismantling the contaminated structure, Bovis Lend Lease, could be dismissed depending on the outcome of the investigations.

“If Bovis can’t answer our questions, they won’t be back on the job,” Mr. Schick said.

Mayor Bloomberg and fire officials have issued a violation against the contractors for a disabled standpipe that left firefighters without a ready water supply to fight the blaze. A maze of debris, polyurethane sheeting, and blocked stairwells also made conditions more hazardous for firefighters.

The building was condemned after it was contaminated by asbestos and other toxins during the collapse of the World Trade Center towers on September 11, 2001. Since the demolition of the building began this year, Bovis Lend Lease and its contractor, John Galt Corporation, have paid thousands of dollars in fines for safety violations. The contractors have been required to hold regular emergency preparedness meetings with updates about conditions inside the building. According to the building’s emergency action plan, the contractors were also supposed to send the fire department updated building drawings as the building was dismantled.

The LMDC referred a question about whether the fire department had an updated building plan on Saturday to the FDNY, which said it was investigating its communications with the contractors.

Fire marshals were still investigating the cause of the fire yesterday, but have pinpointed the fire’s origin to an area where workers often took cigarette breaks.

Yesterday, both the mayor and prosecutors hesitated to say whether criminal charges would be filed in the two deaths.

“At this point there is no reason for anybody to think in terms of criminal charges or anything else,” Mr. Bloomberg said.

A spokeswoman for the Mr. Morgenthau’s office, Barbara Thompson, said prosecutors also believed it was too early to consider criminal charges before the investigation was concluded. The involvement of the prosecutors will give investigators subpoena power.

Mr. Bloomberg dismissed the idea of firing the contractors. “When we went out for contractors to perform this work, there was only one contractor willing to take on the job and we are appreciative of that,” he said. “Without that the building would still be at 40 stories.”

The mayor also defended sending firefighters into the damaged building, saying people work inside the building during the day and the fire department had been uncertain about whether people were inside. What’s more, he added, “You can’t let a fire go out of control” because it could damage the structure of the building or release contaminates into the air.

A group of local elected officials suggested yesterday that the contractors should not have been hired in the first place.

“We warned that the contractors doing the work had huge records of safety violations and the people then in charge ignored us,” Rep. Jerrold Nadler, who represents the area in Congress, said, referring to Governor Pataki’s administration.

The contractors have declined to comment on the fire and did not attend a community meeting yesterday at which they were invited to speak.

Mr. Cuomo has opened his own noncriminal investigation into the fire following calls by the president of the firefighter’s union, Steve Cassidy, according to a report aired on NY1.

A wake for one of the firefighters who died, Joseph Graffagnino, an eight-year veteran and the father of two young children, was held yesterday. His funeral will be on Thursday. The funeral of Robert Beddia, the senior firefighter at the scene Saturday, is scheduled for Friday at St. Patrick’s Cathedral.