BERKELEY (KRON) — Jason Biswas’ parents thought they had experienced a strong earthquake that shook their downtown Berkeley apartment unit early Tuesday morning.

They were unaware that the crash and rumble they felt was caused by a fourth floor balcony that ripped off their apartment complex sending over a dozen people plunging onto the street below.

The 16-year-old Berkeley High School student ran downstairs to investigate what happened and discovered “a bunch bodies” scattered face down on the street.

“I was in the presence of a lot of death. I didn’t want to stay there for too long,” said Biswas.

The accident happened around 12:41 a.m. during a 21st birthday celebration inside an apartment at 2020 Kittredge St., according to Berkeley police spokeswoman officer Jennifer Coats.AUDIO: Listen to the 911 CALL

13 people fell about 40 feet onto the street after a fourth floor balcony collapsed. Four people died at the scene, two died later at the hospital.

Another resident at The Library Gardens apartments described hearing boisterous fun, “like a party,” moments before the deadly accident.

“Like at about 12:30 or 1 o’clock we heard a very huge noise of things falling down,” said Yen Shi.

Officials are still trying to piece together what caused the balcony to fall and they have red-tagged all the remaining balconies at the complex during the investigation.