A motorcyclist who struck and injured a bicyclist in what authorities say was a hit-and-run crash in Larkfield on Wednesday was fleeing an officer who had tried to stop him and two other bikers for speeding, the CHP said.

The motorcyclist remained at large Thursday, but authorities have leads that might help identify him, Officer Jon Sloat said.

The 20-year-old bicyclist, Windsor resident Joel Aguayo, was said to have suffered moderate injuries in the 3:12 p.m. crash and was treated at Santa Rosa Memorial Hospital, authorities said.

The biker who hit him had been riding in a group of three motorcycles on northbound Highway 101, south of River Road, shortly before the crash when a CHP officer came upon them and clocked them at about 90 mph, Sloat said.

The officer activated his lights and siren and attempted to pull over the trio but they kept going, exiting onto Mark West Springs Road, Sloat said.

One of the motorcyclists, Clay Clarke of Clearlake, struck the rear of a GMC Yukon at the exit and crashed in the road, prompting the officer to stop to tend to him, Sloat said.

The other two bikers, meanwhile, left the area eastbound on Mark West Springs Road, where one reportedly ran a red light at Old Redwood Highway and collided with northbound Aguayo, Sloat said.

Witnesses saw Aguayo crawling toward the edge of the road, the CHP said. They described the motorcycle that struck him as a Yamaha R1, with gunmetal or gray paint and black markings.

Officers converged on the area and attempted to find the suspect rider but were unsuccessful, the CHP said.

Clarke, 33, was uninjured, meanwhile, and was detained for questioning. He was found to be unlicensed and was cited and released, though his bike was impounded, Sloat said.

Authorities were still looking Thursday for the culprit in the hit-and-run. He was wanted on suspicion of felony hit-and-run driving and reckless evasion, Sloat said.

Anyone with information on the case can call the CHP office at 588-1400.@pressdemocrat.com.