Eric Larss Peterson, a master of the viola who performed live and on an album as a member of a Twin Cities chamber ensemble, has died.

Peterson, whose talents landed him a prestigious position with the Toledo Symphony Orchestra, was found dead over the weekend near the Mississippi River in Minneapolis. He was 42 and had lived most of his life in Minneapolis.

Police said his body was found early Saturday on the river shoreline on the downtown side of the Stone Arch Bridge. Details about his death have yet to be released by the Hennepin County medical examiner's office.

Peterson's family said that he was homeless, had struggled with mental illness and had just left the hospital the day before his body was found.

Peterson played the violin and viola with Helios, a five-member ensemble whose run from the mid-1990s to 2001 saw the group on Twin Cities stages and in the studio producing two CDs.

He performed on Helios' first CD, "Solar," released in 1999, which a Star Tribune review said "reaches an impressive range of musical landscapes."

The review noted that "lively new works crossing over jazz/classical boundaries by Peterson and composer Arthur Jarvinen add even more variety to the mix."

As a teenager, Peterson was in the Greater Twin Cities Youth Symphonies while attending the Academy of Holy Angels high school, where he was in theater. After graduating in 1987, he studied music at the University of Southern California but had to return to Minneapolis when "mental illness reared its ugly head," said his mother, Becky Peterson.

Eric Peterson resumed his studies at the University of Minnesota and received his degree in viola performance. He immediately became the Toledo Symphony Orchestra's principal viola.

"He had the talent," his mother said. "You've got to feel it, and he had it. ... He always said he was a rock star."

Mental difficulties brought him back home again, where he "pulled it together," Becky Peterson said, allowing him to found the Loring String Quartet, which had a gig every Sunday at the Loring Bar near downtown Minneapolis for a couple of years.

He also was a member of the Minnesota Contemporary Ensemble and filled in with the St. Paul Chamber Orchestra and the Minnesota Orchestra.

He even dabbled in painting, his mother said, having some of his acrylics shown at a south Minneapolis coffee shop.

Friend Angela Lewis was also in theater at Holy Angels and recalled her schoolmate's "brilliant musical mind."

Lewis said his personality reminded her of Peter Pan, "naive at heart and a sweet person."

Along with his mother, Eric Peterson is survived by siblings Karl and Britta. He was preceded in death by his father, Lawrence. Funeral arrangements were incomplete as of Monday afternoon.

Paul Walsh • 612-673-4482