Security video captured a small plane taking off from a southern Utah airport just before it crashed about 300 yards from the runway, killing all four men aboard, a federal investigator said Sunday.

Zoe Keliher of the National Transportation Safety Board said the video shows the single-engine Cessna 172 flying at a low level almost the length of the runway before making a rapid ascent early Saturday morning at St. George Municipal Airport.

"Shortly after that, you see a descent of a few flickers of light but not the plane," she told The Associated Press, adding it's too early to say whether the airport's camera video will offer clues into the cause of the crash.

Marc Mortensen, assistant to the St. George city manager, said officials believe the four men aboard the plane were killed upon impact. The wreckage wasn't discovered until more than four hours later because the airport is not staffed at night, he added.

The victims were identified Sunday as Colby Hafen, 28, and Christopher Chapman, 20, both of Santa Clara; Tanner Holt, 23, of Washington City; and Alexander Metzger, 22, of St. George.

Keliher and Mortensen said they were unsure where the plane was headed at the time. Keliher said only one of the four men had a pilot's license, but neither she nor Mortensen would identify the plane's pilot.

Holt's friend, Paul Hogue, told the Deseret News that Holt was a trained pilot who had flown commercially.

"The future can be taken from you so quickly and they had so much for their future," Hogue said. "They had future families and future wives and kids."

According to Federal Aviation Administration records, the Cessna 172 was built in 1999 and owned by Diamond Flying LLC of St. George.

Keliher said a cursory check of the plane's maintenance records turned up no major problems. She and representatives of Cessna and the company that built its engine inspected the aircraft after it was moved Sunday to a nearby hangar, she said.

It will take months for her agency to examine the plane and pilot, and issue a final report, she said. The NTSB will issue a preliminary report on the crash in five days.

"I'm now trying to get ahold of family members (of the four), and will finish the inspection of the aircraft Monday," Keliher said Sunday evening. "I hope to wrap up the on-scene investigation and leave Tuesday."

According to the National Weather Service, there were no severe weather conditions at the airport during the early morning hours on Saturday.

The airport, which has been in operation at its current site for about 1 1/2 years, does not have a control tower. Pilots use an automated system to communicate with one another when landing or taking off.

Hafen's family issued a statement describing him as a "wonderful son, brother and uncle" who loved to travel and who served a Mormon church mission to Oregon. He worked in the insurance business with his father.

"The community is grieving together," Mortensen told the AP. "St. George is a tight-knit community, and some of the families involved have been in the area over 100 years. If you live in this area, you know someone who knows one of these men."