DORAL, Fla. – The three men who were killed when a five-story parking garage that was under construction at Miami-Dade College West collapsed were identified on Thursday.

Carlos Hurtado De Mendoza, 48, and Jose Calderon, 60, were found in the debris on Wednesday. Samuel Perez, 53, had both of his legs amputated when he was pulled from the rubble early Thursday but later died at the hospital.

"Once this gentleman who was trapped inside his vehicle was extricated, there were no longer anymore live search dog hits, so we turned it into a recovery operation," said Miami-Dade Fire Rescue Lt. Arnold Piedrahita.

A fourth person, identified by his family as Robert Budhoo, an electrical worker from Tamarac, is still missing. The mission to find him is being considered a recovery operation.

"We feel that, at this time, the chance of survival of anyone still left in that debris is minimal," said Miami-Dade Fire Rescue Capt. Louie Fernandez. "We never want to give up. We never want to end the search but, at this time, we are moving forward with our recovery operation."

Heavy machinery was brought in to aid with the recovery efforts instead of firefighters scouring the debris pile.

"This is very complex, very delicate. You just can't go around moving tons of concrete because you might injure or kill the rescuer," said Piedrahita.

"The debris has to be analyzed, the engineers need to be spoken to, everyone is going to need to be interviewed," said Miami-Dade Police Lt. Rosanna Cordero-Stutz.

Three killed, seven injured in accident; One still missing

Miami-Dade police named seven people -- Porfirio Apolinario, 47; Francisco Castaneda, 32; Anthony William, 27; Joseph Barnes; Meregilio Castillo; Frank Stankus, 56; and, Mark DiBacco, 48 -- who were injured. Some of those injured have been released from the hospital. Others remain in stable condition.

Bill Byrne, the president of Ajax Building Corporation, offered his condolences at a news conference on Thursday morning.

"On behalf of my colleagues at Ajax Building Corporation and as well as our partners -- Harvard Jolly, Coreslab, MAR, and others -- we continue to grieve the losses suffered here in Miami," said Byrne. "The entire Ajax Building Corporation team sends our deepest sympathies and prayers to the families of the workers who died and those injured in yesterday's accident at our job site for the new parking garage at Miami-Dade College West in Doral."

Byrne said the three men who died worked for Ajax's subcontractors. No students or staff were injured.

What caused the collapse?

Byrne said it was too early to know the cause of the collapse.

"While we do not yet know the cause of this tragic collapse and it is far to early to speculate," said Byrne. "We have no indication of any potential cause or reaction of what's happened."

Some were concerned the $22 million project was being rushed to meet its scheduled opening in December.

"I think it was on schedule. I don't know that it was hurried. Every construction project is fast paced because time is money," said Byrne.

Byrne said the his company has built structures with similar precast concrete molds before. A spandrel beam was the precast piece of concrete that was being put in place when the collapse happened. It's unclear if that triggered the collapse, and it may be weeks before an answer is given.

Byrne said when the investigation is complete, workers would remove the debris and then reconstruct the facility. OSHA investigators arrived Thursday.

"This is really an outlier situation. In the 52 years of the college's history, we've never had a problem -- at all -- not even a slight blemish until now," said Juan Mendieta, the Director of Communication at Miami-Dade College.

Mendieta said the college uses independent inspectors for permitting.

"By state statue, we have a self-permitting process, and we have a rigorous inspection process," said Mendieta. "So, we're obviously very concerned about this. We're taking this as thoroughly and seriously as possible and over the next few days, we hope to get to the bottom of what happened, and obviously before the main campus building can reopen, we want to make sure that everything is absolutely safe for everyone involved."

Structural engineers are expected to look at the building in the coming days, said Mendieta. The campus will be closed through at least the weekend.

The five-story garage, located at 3800 Northwest 115th Street, collapsed about 11:40 a.m. Wednesday. Firefighters said the floors of the garage collapsed on top of each other, describing it as a pancake collapse.

Northwest 115th Avenue between 34th and 41st Street will remain closed throughout the week.