Investigators are searching the Wisconsin River for a 23-year-old Marshfield man police say shot at them, then escaped on foot.

Eroll Demmerly was last seen running towards the river before disappearing in Rothschild early Sunday morning.

Police say they're only about a quarter done with their search after today because they had to stop early today due to windy conditions.

They're using a sonar imaging device, one of only two in the Midwest; the other is in Chicago.

The Marathon County Sheriff's Department bought it last year.

It was used to recover a body in Minnesota last year, but is being put to use for the first time locally.

The device will help them search the river much quicker then a team of divers could.

The Marathon County Sheriff's Department hopes to continue the search tomorrow.

They are considering Demmerly armed and dangerous, and say he had an AR-15 Superior semi-automatic rifle, and a Browning semi-automatic pistol - both with makeshift silencers.

Nearly 300 rounds for the weapons and camouflage were also found in the vehicle.

A $1000 reward being offered to anyone with information that leads to Demmerly's arrest.

If you have any information, call Marathon County Crime Stoppers at 1-800-559-4203.