RICHMOND - Authorities trying to communicate with the Washington-area sniper issued a second cryptic statement Monday, saying they have received a message and were preparing a response.

In the second day of dramatic developments, police in the Richmond suburbs surrounded a gray and white van parked next to an outdoor phone. They later towed it away. There were unconfirmed broadcast that two people were in custody.

In his brief statement issued in Maryland, Montgomery County Police Chief Charles Moose didn’t specify whether the message was a new communication or the same one they discovered near the scene of the latest shooting Saturday night.

“The message that needs to be delivered is that we are going to respond to a message that we have received,” Moose said. “We are preparing our response at this time.”

Moose left the podium immediately after the statement, and said beforehand he would not take any questions.

Police found a note in the woods near the Ponderosa restaurant in Ashland, Va., a few miles north of Richmond, after a man was shot and critically wounded Saturday night.

Police in Hanover County, Va., where Saturday’s shooting took place, told reporters that the van had been stopped along Broad St. a major commercial street.

“It was specific enough to be a suspect vehicle in all the cases,” said Lt. Doug Goodman of the Hanover County Sheriff’s Department. A police officer at the scene said the van was a Plymouth Voyager with temporary Virginia tags. He did not confirm broadcast reports that anyone had been taken in for questioning.

In a brief but dramatic news conference late Sunday, police had urged whoever left the note at the scene of Saturday’s shooting to call them.

“We do want to talk to you,” Moose said Sunday.