B.C.'s Peace Arch border crossing reopened to southbound traffic Wednesday following a 24-hour shutdown sparked by the shooting of a Canadian border officer.

The crossing into the U.S. reopened at 4 p.m. PT, but here was still no word from Canadian authorities when the northbound lanes would reopen.

The border officer who was shot at the busy crossing south of Vancouver by a lone gunman is expected to make a full recovery, a union official says.

The female guard, Lori Bowcock, was shot in the neck by the gunman, who then turned his gun on himself and died from what police said was "a self-inflicted gunshot wound."

Police have not officially released the name of the gunman, but sources told CBC News that they believe he was Andrew Crews of Bremerton, Wash. Officers reportedly raided Crews's Seattle-area home on Wednesday morning.

The victim, Bowcock, who is in her late 20s, moved from Ontario to B.C. to work for the Canada Border Services Agency a few months ago, the Ontario Provincial Police confirmed Wednesday.

RCMP Cpl. Bert Paquet said the gunman, who was driving a white van with Washington licence plates, approached the border kiosk and shot the officer in the neck. Bowcock was airlifted to a Vancouver hospital with a serious injury.

Customs and Immigration Union spokesman Jason McMichael said Wednesday that Bowcock is expected to make a full recovery.

Police have been reviewing surveillance video and interviewing witnesses, but have not indicated any possible motive for the shooting.

Few other details have emerged about the incident, which took place around 1:30 pm PT Tuesday at the Peace Arch crossing between the U.S. and Canada.

The incident prompted officials to close the crossing between Surrey, B.C., and Blaine, Wash.

LeAnn Dombrosky was in her car near the kiosk where the shooting occurred around 2 p.m. PT.

B.C. Premier Christy Clark and Washington Gov. Chris Gregoire have spoken about the shooting. Police on both sides are working together on the case. (Jonathan Hayward/Canadian Press)

"There was a gunshot and sounds of a woman screaming which drew the attention of all the other guards," she said in an email. "Then after about 10 seconds, the guards were yelling to a man in a white van in the far left lane [closest to the building]to put his hands up —another shot or two were fired — in which the driver of the white van took his life with a bullet in his head."

Politicians in B.C. and Washington have pledged to co-operate during the investigation.

B.C. Justice Minister and Attorney General Shirley Bond says Premier Christy Clark and Washington Gov. Chris Gregoire have spoken about the shooting, and police on both sides will work together.

Gregoire said she considers Canadian guards an "extension of the Washington family" because of their help in protecting the border.

Before moving to B.C. to work for the CBSA, Bowcock was an auxiliary Ontario Provincial Police constable in southern Ontario, OPP spokesman Sgt. Dave Rektor said.

"She is a very well-liked person and certainly our thoughts and prayers are with her right now. Everybody in the area is hoping for a speedy recovery for Lori, and of course we're staying in contact with family and investigators to get updates."

'Sobering reminder of the dangerous conditions'

Luc Portelance, president of the CBSA, issued a statement saying, "This is a profound reminder of the risks that border services officers assume every day. I know that the courage and dedication of our officers are second to none."

Public Safety Minister Vic Toews said in a statement that his thoughts and prayers are with the officer's family and colleagues.

"I am deeply concerned by the news of the shooting today at the Peace Arch border crossing of a CBSA officer," Toews said. "This event is a sobering reminder of the dangerous conditions faced daily by the men and women of our law enforcement agencies."

Located about 40 kilometres south of Vancouver, the Peace Arch, officially called the Douglas crossing, is the third-busiest border point between Canada and the U.S.

An average of 3,500 cars pass through the crossing on a slow day, and during peak periods about 4,800 vehicles will move through the border.

During those peak periods, border delays can reach four hours on either side of the border.