Horrific moment man randomly hits 90-year-old with cane in NYC

Surveillance video has captured the shocking moment a 90-year-old man was hit in the head in an unprovoked attack on Friday.
NYPD officers say the assault occurred in the neighborhood of Inwood in Manhattan around 5:55pm.
The callous attacker is walking down the street when he notices the elderly gentleman and gives a swift kick to his shopping cart.
He then deliver a vicious strike to the side of the 90-year-old's head with a cane.
Passersby are briefly stunned by the sudden assault, but one Good Samaritan quickly jumps in to try and break up the fight.
He even delivers a punch to the attacker before he manages to run off west on Broadway.
Meanwhile, the elderly man is seen clutching the side of his head.
Those who live in the neighborhood describe him as 'frail, walks around collecting cans, and doesn't bother anyone', reports ABC 7.
Medics rushed the victim to a local hospital, where he was treated for lacerations to the head and ear. According to police, he is in serious but stable condition.
The motive for the elderly man’s assault remains under investigation, but appears to be unprovoked, sources said.
The suspect is described as between 20 and 30 years old, dark-skinned, and around 5'10" and 150 pounds.
He is seen on the video wearing headphones over a blue Yankees baseball cap, a black T-shirt over a gray long-sleeved shirt, pajama bottoms with checker box print and black sneakers.