Story highlights Firsthand accounts are helping build a picture of why the boat capsized

Lampedusa is a common destination for African refugees

There's been criticism more was not done to help

Survivor: "My mind is scarred"

At the port in Lampedusa, recovery teams continue to fill trucks with the bodies they're still pulling from the sea.

More than 190 so far -- and climbing.

They are among 500 African immigrants believed to be aboard a boat that sank off the island Thursday in Italy's deadliest migrant shipwreck.

The survivors -- 155 of them, mainly from Eritrea -- wait in a cramped migrant detention center. It was built to hold 250 people but houses more than 1,200.

Germani Nagassi, 30, told CNN he'll never forget what he saw.

"For five hours we were floating, using the dead bodies of our companions," he said. "There is nothing worse than this. There were many children. There was a mother with her four children, a mother with an infant, all lost at sea. My mind is scarred and in a terrible condition."

The traumatic first hand accounts are helping build a picture of why the boat ended up on the seabed of the Mediterranean with most of its passengers entombed below deck.

JUST WATCHED Dozens dead in Italian boat accident Replay More Videos ... MUST WATCH Dozens dead in Italian boat accident 01:10

13 days at sea

The vessel was packed with hundreds of African migrants.

Because of its location as the closest Italian island to Africa, Lampedusa is a common destination for African refugees seeking to enter European Union countries, and shipwrecks off its shores are common.

Survivors described spending 13 days on the boat before the engine stopped less than a mile from the small Mediterranean island, halfway between Sicily and Tunisia.

There's been criticism more was not done to help, that the Italian Coast guard was too slow to respond, that they spent precious time filming footage of the rescue instead of saving more lives.

Hamid Mohammad, 18, swears an Italian vessel spotted them in trouble off the coast, but did nothing.

"The Italian's boat started circling around us. They circled our boat twice, then just went away," he said. "That's when people started to panic."

Fire on board

The boat's captain told the passengers to set fire to clothes and blankets to attract attention.

"He gathered some clothes and bed sheets and lit them. But his container of benzene exploded," Mohammad said.

The fire then spread and when many of the migrants crowded to one side, the boat capsized, said Italian lawmaker Mario Marazziti, citing survivors' accounts.

"People were screaming as the boat capsized," Mohammed said.

The lucky few

In response to criticism, the coast guard Saturday defended its response time and said its crews were on site 20 minutes after receiving the SOS call.

"The moment we got the emergency call from the fishermen at 7 a.m. we immediately intervened and started coordinating the rescue operations," said coast guard spokesman Filippo Marini

Abrahalli Amare, 23, was one of the lucky few who were eventually rescued.

"We left our country because of hardship, so that we could live in peace and help our families," said Abrahalli Amare, 23. "But we have found this bitter sadness. It was so unexpected, so disturbing. And now we can't think of anything else,"