Authorities in Dakota County are scrutinizing pieces of a pickup truck and pleading for the surrender of the motorist who hit and critically injured a seasoned bicyclist who left work on a long county ride “to enjoy the weather.”

Bryan W. Joas, 45, of Eagan, was run over from behind late Tuesday afternoon while bicycling east on 250th Street W. at Highview Avenue in Eureka Township, authorities said.

Joas was flown by helicopter from the scene in the southwestern edge of the county to North Memorial Medical Center in Robbinsdale, where he was in critical but stable condition, said Sheriff Tim Leslie.

“His wife assured us he’s going to live,” the sheriff said.

Leslie said Joas was making a meandering ride home from his job in Burnsville, which he occasionally does. Sometimes these rides run 50 to 75 miles, his wife told the sheriff. Joas has participated in long-distance races in the region.

On Caringbridge.org, Shauna Joas explained that her husband left work about 4 p.m. on a balmy early March day “to enjoy the weather. At 7, I started getting worried and began calling and texting him.

“At around 7:45, two Eagan police officers came to the door to tell me Bryan had been in a serious accident and was airlifted to North Memorial hospital in Robbinsdale.”

In a follow-up posting, she wrote, “This is truly a biker’s wife’s worst nightmare.”

Bryan Joas suffered several internal injuries, a broken back, hip and ribs, some of which were likely inflicted when he struck a mailbox on a pole outside a home, Leslie said. He was wearing a helmet, which spared him any head injuries, the sheriff added.

A Caringbridge.org posting Wednesday afternoon said Joas underwent surgery to remove much of his large intestine but his kidneys “are not working.”

Speaking about the motorist who fled, the sheriff said, “We need the person who did this to come forward and straighten this out. It’s only going to get worse.”

Authorities are asking for the public’s help in finding a white pickup truck with large tires and red highlights that was seen in the area after the crash. The vehicle may have front-end damage. Anyone with information is asked to call 651-438-4721.