Boy, 3, dies falling into restaurant's grease trap in 'unimaginable' tragedy

A three-year-old boy died after falling into a restaurant's grease trap in an "unimaginable" tragedy, police say.

The toddler had been taken to work with his mother at doughnut and coffee shop, Tim Hortons, in Rochester, New York.

Shortly after 11am, the mum called police when she realised her son had vanished from her side.

His body was found just minutes later by "a witness" who saw him in a grease trap behind the restaurant on University Avenue.

Rochester Police Investigator Francis Camp said the witness attempted CPR on the boy as did officers and paramedics - but he was pronounced dead in hospital.

The toddler died at the branch on University Avenue in Rochester, New York (13WHAM)

Police tape surrounds the scene where the three-year-old boy fell into a Tim Hortons grease pit (ABC)

Officer Camp said the boy had been found in a grease pit similar to a manhole which was located just yards from the rear of the restaurant, reports Fox News .

The lid covering the pit was plastic and it gave way when the boy stood over it, police say.

Camp added: "It looks like it was an unsecured lid."

He added it was a "horrible, horrible, unimaginable, unspeakable tragedy."

Police cars at the scene after the little boy was found in the pit at the rear of the restaurant (ABC)

An investigation has been launched into the tragedy (ABC)

Employees at the Tim Hortons Rochester branch were seen being comforted by police after the horrific tragedy.

In a statement, Tim Hortons said: "What occurred today was a tragedy and on behalf of the Tim Hortons family, we offer our deepest condolences to the family and friends of the young boy who passed away."

An investigation into the incident has been launched.