NEWARK, N.J. — The owner of a small plane who perished along with four others, including three Polish tourists, in a 2010 crash told a friend that the aircraft was leaking fuel and oil on the day of the crash, according to documents recently released from a federal investigation.

The friend, an airplane mechanic, also told investigators he had previously cautioned owner Jacek Mazurek against performing a specific aerial maneuver that the pilot may have attempted just before the accident.

"I'm like, 'You can't do that with this airplane, it's not built for that,'" Michael Petrossian told The Associated Press on Tuesday. "I guess he didn't heed my warning and did it again anyway."

The February 2010, crash killed Mazurek, who lived in Kearny in northern New Jersey; 46-year-old Wojciech G. Nykaza, of Lodi, N.J.; 38-year-old Andrzej Zajaczkowski of Warsaw; his 14-year-old son, Patryk; and his 6-year-old nephew, Filip Zajaczkowski. The three Polish tourists were family friends of the 45-year-old Mazurek.

Nykaza and Mazurek both were certified pilots, according to the National Transportation Safety Board's preliminary report released a week after the accident, but it isn't known which man was operating the controls at the time of the crash.

Other family members were at Monmouth Executive Airport watching when the plane crashed, and eyewitnesses described seeing a man believed to be the father of the 6-year-old rush to the scene and pick up his son from the wreckage.

The interviews with eyewitnesses and others are contained in files released last week by the NTSB. The agency has not released a final report on what caused the accident.

Petrossian told investigators the day after the crash that he had met Mazurek, whom he referred to as Jack, several years before and had performed work on the Cessna.

He said Mazurek called him on the day of the crash to tell him fuel and oil were leaking from the rear engine.

Petrossian said he told Mazurek not to fly the aircraft until they could figure out where the fluids were coming from. He said he thought Mazurek was only going to run the engine to try and identify the leak's source, not fly the plane, on the day of the crash.

Petrossian also told investigators he had warned Mazurek a year earlier about performing low fly-bys followed by a hard pull-up because the Cessna "was not designed for that type of operation." He said Mazurek had played videos showing him performing the maneuver.

Reached at his home in Florida on Tuesday, Petrossian confirmed the contents of his statement and recalled warning Mazurek about the maneuver.

Several people who witnessed the crash described the plane flying low past the airport at high speed, then pitching upward before losing part of a wing and cartwheeling into the snow. According to NTSB files, GPS data from the plane showed it was going 160 knots, or more than 180 mph, about 140 feet in the air right before it crashed.

The crash spurred the Federal Aviation Administration to issue a directive to owners and pilots of certain Cessna Skymaster 336 and 337 series aircraft to make inspections.