Claresholm RCMP are investigating a roadside shooting that left four dead and one in hospital early Thursday morning, and forced police to close a major highway for several hours.

RCMP were called after 3 a.m. Thursday morning by a passing driver, who noticed two vehicles on the side of Highway 2.

"Our information right now is that there were four people in one vehicle, and one individual in a second vehicle," Sgt. Patrick Webb said Thursday.

Two men and one woman were confirmed dead at the scene, later investigators determined two were murdered, and the third died as a result of suicide.

Another man and woman were taken to hospital in Calgary, where the man later died.

RCMP said the woman is expected to recover from her injuries.

Later in the day, the Charlottetown Guardian confirmed the identities of three of the people involved in the tragedy.

According to the newspaper, two of the men who were shot and killed have been identified as Tanner Craswell and Mitch Maclean, baseball players in their 20s who were attending the Canadian Baseball Academy in Lethbridge.

The woman recovering in hospital has been identified as Shayna Conway, according to the Guardian they were travelling to the Calgary Airport to return to Prince Edward Island for the holidays.

RCMP have not released the identities of the other people involved.

Investigators said they are looking into the possibility the shooter and the woman who died on the scene were domestic partners, and that he may have run her off the road.

Highway 2 was closed in both directions for several hours Thursday as police carried out their investigation, both directions opened mid-afternoon.

With files from Kim Taylor