RIVERDALE, the Bronx (PIX11) — One swimmer, 59, was killed, and another, 72, was critically injured when a tree fell over and into the pool where they were swimming on Monday afternoon, officials said.

Police are investigating the incident, but eyewitnesses said that it appeared to be a tragic, and very disturbing, accident. 

“I looked down at the pool and saw the tree hit the water and saw one person moving away from where the tree was very quickly and saw the fatality lying face down in the water with a huge amount of blod in the water,” said a neighbor of the high-rise condominium where the tragedy happened.

The eyewitness, who only gave his first name, Matt, said that he heard the tree crack and crash.

It happened at 2621 Palisade Avenue, a luxury building that overlooks the Hudson River, at around 1:35 p.m. 

Neighbors said that the victim had lived in the building for about five years. No official identification has yet been made.

The New York City Parks Department also investigated, but said that the tree, which is near riverside forested land, and Metro North railroad tracks, is not in its jurisdiction.

The tree appeared to be on the property of the building where it fell. 

Witnesses said that the situation underscored how urgent it is to know how healthy — or unhealthy — a tree is. 

“There was no wind today,” said another local resident, Norman Liss.

He called what had happened to his neighbor a tragedy. 

“It must have been a tree that was really in trouble. Wow,” Liss said.

His neighbor, Matt, talked about the situation further, saying that trees that are in areas where people congregate need to be “taken care of by arborists to determine whether they should be pruned, trimmed, treated. “

He said that what he saw and heard he won’t soon be able to forget.

“[It sounded] like a tree limb, falling off of a tree, cracking off of a tree,” he said, adding that it was “freaky. Freaky.”