JANESVILLE - Police officials say a reported shooting and standoff on East Racine Street in Janesville on Sunday was apparently a hoax.

After police cordoned off streets for blocks around a duplex rental property at 329 E. Racine St. and sent in a swarm of officers and a SWAT team, police found the residence empty.

The situation began when emergency crews responded at 4:20 p.m. Sunday to the residence for a report of a gunshot victim and a hostage situation.

A male subject told dispatchers he shot his mother and was holding his brother hostage at the residence, according to police scanner chatter. Police later confirmed they were responding to a possible standoff.

On Sunday night, Janesville police Sgt. Mark R. Ratzlaff said police were still investigating the call, which came from a "restricted line," but police didn't know who made the call. No one was apparently injured or being held hostage in or near the residence, and there were no immediate suspects in the incident, Ratzlaff said.

"It appears it was a hoax," Raztlaff said in a press conference. "We have not been able to substantiate claims in the phone call, but we're checking loosely related addresses to verify nothing occurred and to make sure that there aren't incidents happening anywhere else."

Ratzlaff said police and SWAT officers checked both sides of the duplex, which are connected, and found no one inside.

Emergency crews were sent back to their quarters, and officers began cleared the scene around 6:30 p.m.

Police with rifles had cordoned off streets for blocks around Main and Racine streets. Officers were positioned behind squad cars and in trees across the street, and they were telling neighbors to stay in their houses, he said.

Others who were coming home during the situation were directed to an air-conditioned Janesville city transit bus parked at the corner of Main and Racine streets.

Police responded with a swarm of officers, including tactical and SWAT officers, and Janesville police and Rock County sheriff's officers were armed at street corners with rifles to keep people from getting too close to the home on Racine Street.

Ratzlaff said the heavy police and emergency response was part of protocol under state statute for active shooter and hostage situations.