Two boys killed in a massive pileup on Highway 401 near Whitby last week were vacationing with their parents from Mexico, Mexican officials have confirmed.

Raul Saavedra, with the Mexican Embassy in Ottawa, told CTV News the boys’ father, who was also seriously hurt in the collision, is a lieutenant colonel in the Mexican military who was participating in a language-related exchange program in Canada.

Saavedra said the officer and his wife are recovering in hospital. Mexican consular staff are providing assistance to the family and visiting with them each day. Their names have not been released.

The collision occurred on the westbound lanes of Highway 401 near Salem Road in Whitby at around 10:30 p.m. Friday.

A transport truck failed to slow down for construction and collided with cars ahead of it, causing a string of collisions that eventually involved two other transport trucks and 17 other smaller vehicles.

Two adults and the Mexican couples’ 12-year-old son died at the scene. Their other son, 10, died in hospital Sunday.

Charges have not yet been laid in connection with the crash, police said.