The province’s police watchdog says two officers at the centre of the investigation into a fatal wrong-way crash on Highway 401 in Whitby earlier this year have not agreed to be interviewed or submitted their notes to investigators.

In a news release issued Wednesday, the Special Investigations Unit (SIU) said seven investigators with the arms-length agency are continuing to probe the Durham Regional Police Service’s handling of the April 29 crash, which left four people, including an infant, dead.

At around 7:50 p.m. on the night of the collision, officers pursuing suspects wanted in a liquor store robbery in Bowmanville followed their fleeing cargo van onto Highway 401 at Stevenson Road, travelling westbound in the eastbound lanes of the highway.

The police pursuit ended in tragedy when the suspect vehicle caused a pileup that killed an infant, the child’s grandparents, and one of the suspects.

In an update on Wednesday, the SIU said that while interviews are ongoing, the two subject officers have not submitted their notes or agreed to be interviewed, which is their legal right.

Nineteen witness officers have been identified and another 36 civilian witnesses have been interviewed, according to the SIU.

“At this time, the SIU is in possession of more than 100 videos, obtained from: in-car camera footage, drone footage, body worn camera footage, Ministry of Transportation footage and civilian recordings,” the news release read.

The SIU also confirmed Wednesday that the other occupant of the fleeing cargo van, a 38-year-old man, remains in hospital.

“The SIU is urging anyone who may have information about this investigation, including video or photos, to contact the lead investigator at 1-800-787-8529,” the release concluded.