A 15-year-old boy and his teenage girlfriend were the two people killed when their car and a transport truck collided near Freelton on Thursday.

The Special Investigations Unit says 15-year-old Nathan Wehrle of Cambridge, Ont., and 16-year-old Taryn Hewitt of London, Ont., were killed when their car hit the truck head-on in rural Hamilton.

Wehrle's sister Chloe says he was the sort of person who loved to help other people – even if that meant taking his birthday money and spending it on his friends.

“There was nothing else that he would rather do than make somebody else happy,” she said Friday.

Wehrle and his girlfriend were pronounced dead at the scene of Thursday morniing’s collision on Highway 6.

Few details have been released publicly about what happened in the half-hour or so prior to the crash, which occurred at 9:55 a.m.

Waterloo Regional Police say they received a call around 9:30 a.m. about a possible abduction and/or assault on King Street East in the Preston part of Cambridge.

One woman who was in the area at the time told CTV News that she saw a red car parked on the wrong side of King, with a man and a woman inside. The woman yelled at the man for some time, she said.

Police say they attempted to stop the vehicle, but found the driver unwilling to co-operate.

A pursuit ensued. It’s not clear if police continued the pursuit after leaving Waterloo Region, although multiple WRPS vehicles were present at the crash scene in its aftermath. The crash occurred 15 kilometres outside the region, in the City of Hamilton.

Chloe Wehrle says the car they were in had been stolen from a friend of hers, but any suggestion of an assault or abduction is wildly out of character for her brother.

“I just want everybody to know that my brother would never do something like that,” she says.

“Stealing cars was his thing. Killing people – abducting people – was not.”

Due to the police involvement, Ontario’s Special Investigations Unit has been called in to look at the crash and the events leading up to it.

Waterloo Regional Police have turned their internal investigation into it over to the OPP.

“Because this primary investigation … does involve members of our organization, we’ve asked the Ontario Provincial Police to conduct an independent investigation,” Insp. Michael Haffner said Friday.

“We’re asking the OPP to conduct a fair and transparent investigation on our behalf.”

Part of the investigation involves security video from King Street East in Cambridge. The owner of a pizzeria there says he has handed off footage from Thursday morning to police.

With reporting by Abigail Bimman