BOULDER, Colo. -- As the investigation continues into a mid-air crash involving two small planes in North Boulder, family and friends of the victims are remembering two brothers who lost their lives.

"Just a great guy, just a family man, always there for you," said John Annear.

Annear said he’s been friends and next-door neighbors with 56-year-old Mark Matthews for more than 20 years.

Family members confirmed Sunday, Mark Matthews and his 58-year-old brother Bob Matthews, were both on the Cirrus plane that collided with a Piper Pawnee Saturday afternoon.

Annear said the plane belonged to Bob Matthews.

"He was a very conscientious pilot. No safer pilot that I’m aware of," said Annear.

He said the two brothers were very close and enjoyed spending time together.

"And that was Saturday. It was just a pleasure ride around the Boulder area," Annear said.

How it turned so tragic is still a mystery.

"It was described as immediate disintegration and explosion of both airplanes," said NTSB Air Safety Investigator Jennifer Rodi.

Investigators spent the Sunday searching through the wreckage, marking and collecting evidence in the debris zone. They also said they have a radar recording leading up to the crash site. They’re hoping that, along with witness photos and interviews will provide answers.

"Unfortunately, we may not be able to answer factually where the pilots were looking just prior to the collision," said Rodi.

Meantime, family and friends wait anxiously. They’re holding tight to each other and to memories of happier times.

The family released this statement Sunday: "Mark and Bob were men who were dearly loved. Wherever they went, they impacted their community with their integrity, kindness, humor and love. They will be sorely missed by their adoring wives, children and family and friends."

Neighbors also told 7NEWS the two brothers were very involved in their community. Annear said Bob Matthews was a water rights lawyer, in Boulder. Mark Matthews owned an engineering company, in Englewood.

The Boulder County Coroner has identified the third victim, the pilot of the Piper Pawnee, as Alexander Howard Gilmer, 25, of Evergreen.

His family asked for their privacy.

On his MySpace page, he described himself as a base jumper, sky diver, pilot and Marine.