Boston woman, 26, dies in hospital after being mowed down in road rage killing ... trends now

A road-rage driver got back in his car and steered it through two u-turns before accelerating into a young woman, leaving her fatally injured on a Massachusetts highway, prosecutors have alleged.

Destini Decoff, 26, died in hospital on Sunday less than 72 hours after she was hit at speed by Ryan Sweatt's Honda Civic on Route 85 north of Milford.

Sweatt, 36, told police that he had been threatened with a knife by the four men in Destini's car during the incident at 6pm on Thursday.

But surveillance footage shows him turning round and steering into the group of friends rather than driving off, police claim.

'He turned around multiple times and he coulda just kept going,' witness Brett Martin said.

'He could have kept going. He chose to turn around, chose to come back. He knew what he was doing when he went towards that girl.

'I didn't see her go up in the air. But I saw her come down, hit the pavement. It wasn't good from there.'

'I saw her mid-air kind of coming down towards the street, her jacket must've been 20 feet away from her. However she got hit, those clothes flew off.'

Sweatt told police he had left work and was driving home to Milford when the other car pulled in front of him, and its driver slammed on the brakes.

A police officer caught up with Sweatt and saw damage to his windscreen after seeing him speed away.

'They're trying to kill me,' he told the officer, gesturing back to the people gathered around Destini who was lying in a pool of blood.

Destini, 26, was taken to hospital suffering from a brain bleed, collapsed lungs, and fractures to her shoulder, tibia and ribs.

She had an emergency operation to remove her spleen and part of her skull to relieve pressure on her swollen brain but never regained consciousness.