BBC News Online details the developments leading to the arrest of the two suspects in the Washington area sniper case.

Wednesday 23 October

FBI agents conduct a metal detector search of a house in the Tacoma area on the west coast of the United States apparently looking for shell casings and bullet fragments.

Police later issue arrest warrants for John Allen Muhammad (also know as John Allen Williams) and a younger, unidentified man believed to be his stepson whom they warn are both armed and dangerous.

You asked us to say, 'We have caught the sniper like a duck in a noose'. We understand that hearing us say this is important to you

Police Chief Charles Moose

Montgomery County Police Chief Charles Moose says both "may have information material to our investigation" and are wanted on what he describes as "federal firearms violations".

However Chief Moose cautions against any implication of either man's involvement in the recent shootings.

It is reported that Mr Mohammed had served in the US military at Fort Lewis in Tacoma.

Police also issue a description of a 1990 Chevrolet Caprice car with New Jersey number plates wanted in connection with the case.

On Wednesday evening, Police Chief Moose delivers another cryptic message, apparently to the sniper, during a press conference:

"You asked us to say: 'We have caught the sniper like a duck in a noose'. We understand that hearing us say this is important to you. However we want you to know how difficult it has been to understand what you want."

Police described John Allen Mohammed as armed and dangerous

The reference to a duck and noose is thought to be from a folk tale, in which a rabbit attempts to catch a duck in a noose but ends up thwarted by the duck, according to the Washington Post.

"Let's talk directly," Chief Moose continued.

"We have an answer for you about your option. We are waiting for you to contact us."

This is thought to refer to the sniper's demands for $10m apparently left in a note at the scene of one of the shootings.

Thursday 24 October

0100 local time

Police are called to a rest area on interstate route 70 in Virginia by a motorist reporting a car fitting the description issued on Wednesday.

A local state trooper confirms the vehicle's identity and a joint tactical response unit is sent to the rest area.

A seven-mile (11km) stretch of road is closed and cordoned off.

0330 local time

Two men sleeping in the car are arrested without incident.

Police refuse to confirm their identities, but describe the men as African-Americans, one aged about 40 and the other about 20.

Maryland State Police spokesman Greg Shipley says the two are being questioned, while police seek to obtain further search warrants.

The men were identified as John Allen Muhammad, 42, and his 17-year-old stepson John Lee Malvo.

Police also disclose they are following up a possible connection between the Washington shootings and the fatal shooting of a woman in the southern state of Alabama.