Longtime Friends — a Firefighter, a Journalist — Among 5 Killed in East River Helicopter Crash

Two of the five passengers killed when their tour helicopter plunged into the East River Sunday, marking one of the deadliest civilian aviation crashes in New York City history and one of the worst in America in the last few years, are high school friends who were doing sightseeing in the city this past weekend.

Brian McDaniel, a nearly two-year veteran of the Dallas Fire-Rescue Department who worked at Station 36, was visiting his longtime friend Trevor Cadigan, who had been living in New York since October 2017 after taking a job with a business magazine, Cadigan's father said. The two friends were both 26; they went to Texas' Bishop Lynch High School together and graduated in 2010.

The lone female victim has been identified as Carla Vallejos Blanco, an Argentinian tourist who just celebrated her 29th birthday 10 days ago, according to the Argentinian Consul's secretary. Two helicopter employees -- 29-year-old Tristan Hill and 34-year-old Daniel Thompson -- also died.

The chopper was owned by Liberty Helicopter Tours.

Liberty issued its first statement on the crash shortly before 1 p.m. Monday, saying, "We are focused on supporting the families affected by this tragic accident and on fully cooperating with the FAA and NTSB investigations. These agencies have asked us to respect the investigative process by referring all press inquiries to them for any further comment."

The Eurocopter AS350 carrying the five passengers and their pilot went down in the East River near the northern end of Roosevelt Island around sunset Sunday. Only the pilot, identified by sources as 33-year-old Richard Vance, survived.

The pilot called "Mayday!" several times and reported the chopper had experienced engine failure right before the crash, according to the distress call.

Video captured by multiple witnesses shows the chopper hovering in the air, then suddenly descending toward the river, where it crashes, its half-submerged propellers madly spraying water. It overturns, then sinks. Vance managed to escape the flipped chopper. The five passengers were trapped in the inverted aircraft and had to be pulled from frigid waters by divers, officials said.

Cadigan, 26, graduated from Southern Methodist University in 2016 with a bachelor's in journalism. He was an intern at Business Insider until a few weeks ago, the company said, adding it was devastated to hear of his death.

"He was a smart, talented, and ambitious young journalist and producer who was well-liked and made a big contribution," Business Insider said in a statement. "Our hearts go out to his family and friends."

McDaniel is survived by his parents and older brother. 

"Officer McDaniel was single, and had no children, but was immediately survived by his Father, of Dallas; and his Mother and older Brother, of Denver, CO," the Dallas Fire-Rescue said in a statement. "Despite his short tenure, hearts are heavy with grief as we not only try to come to grips with his loss departmentally; but to also be there in every way that we can for his family. The family asks for privacy during this trying time."

Hill, 29 and engaged to be married, was most recently working at a sightseeing tour company but had previously been a basketball operations assistant with the Westchester Knicks, a Development League affiliate of the New York Knicks.

He "brightened every room he entered, with a contagious smile and an unparalleled enthusiasm for life," the team said in a statement.

The National Transportation Safety Board is leading the investigation. A news briefing is expected later Monday. No cause has been officially suggested.

A senior law enforcement official, however, tells News 4 that Vance speculated in an initial interview it was possible one of the passengers inadvertently hit the fuel cut-off switch with a piece of equipment, which may have caused the engine to sputter and the chopper to plunge into the river.