Police are investigating the cause of a crash that injured two motorcycle riders who say they encountered cows in the roadway in Vassalboro.

The operator , Steven Smart, 41, of Warren, and passenger Mary Camber, 38, were taken Monday night by Delta Ambulance to MaineGeneral Medical Center in Augusta to be treated for what police described as non-life-threatening injuries. They were later released from the hospital.

The couple was riding northbound on Riverside Drive around 7 p.m. when they came upon four cows in the roadway, according to Shannon Moss, public information officer for Maine Department of Public Safety. Smart tried to maneuver around the cows and crashed the motorcycle.

State police reconstructed the crash and are still investigating the cause, including why the cows were in the roadway.

Moss said if troopers determine there is probable cause a crime was committed leading to the crash there could be criminal charges.

Maine animal trespass laws indicate an owner or keeper of an animal may not allow it to enter onto or remain on the property of another, or unattended on any local, county, or state road or highway. Doing so could be a civil violation, but only after the animal’s owner or keeper has been informed by a law enforcement officer, authorized employee of the department or animal control officer that the animal was found on that property or on that roadway.

Violators could be subject of a fine between $50 and $500 for a first-time offense and could be required to pay restitution. Maine law also specifies when an animal damages a person’s property due to negligence of its owner or keeper, that person can be liable in a civil action to the person whose property was damaged.

Moss said Wednesday troopers have more interviews to do before they would know whether there will be any charges.

Vassalboro fire Chief Walker Thompson said Tuesday a Vassalboro firefighter came upon the crash, saw a motorcycle and two people lying in the roadway, and immediately called to report it to dispatchers. Thompson said no cows were at the scene when the accident was discovered.

Riverside Drive, also U.S. Route 201, was shut down for about two hours Monday night, between Taylor and Oak Grove roads.

The crash was at 2486 Riverside Drive, just north of the intersection with Oak Grove Road.