Chilling note revealed of machete-wielding teen accused of slashing three NYPD officers at Times Square NYE celebrations

The police officers hurt in the attack are expected to survive

The man who allegedly attacked New York police with a machete on New Year’s Eve penned a letter to his family begging them to accept Islam, police said.

Trevor Bickford, 19, of Maine, arrived in New York City just days before New Year’s Eve and stayed at the Bowery Mission in Manhattan. Mr Bickford carried a handwritten note in his bag urging his family to "repent to Allah and accept Islam," police told The New York Post.

Around 10pm on Saturday Mr Bickford allegedly attacked police working near Times Square, including a rookie cop on his first assignment.

The rookie reportedly suffered a cut to his head, and another officer from Staten Island suffered blunt force trauma to his head. Both were hospitalised with non-life-threatening injuries.

Police ultimately stopped Mr Bickford by shooting him in the shoulder. He was hospitalised over the weekend and has been charged with two counts of attempted murder and two counts of attempted assault.

The machete used in a New Year’s Eve attack on NYPD officers near Times Square (NYPD)

Law enforcement has not determined a motive for the attack, but information found in the letter may shed some light on Mr Bickford’s frame of mind ahead of the alleged machete assault.

"To my family — specifically, mother — I’m sorry for not having been a good enough son," Mr Bickford wrote in the note. "I fear greatly that you will not repent to Allah. And therefore I hold hope in my heart that a piece of you believes so that you may be taken out of the hellfire."

He also addressed his brothers in the letter.

"To [my brother] Travis. Of anyone I’ve known who I have felt is closest to faith — it’s you," Mr Bickford allegedly wrote. "Of anyone I’ve ever wanted to accept Islam with me — it’s you. Please repent to Allah and accept Islam. I fear for you."

The letter suggested his relationship with his brother Devon had become strained prior to the attack.

"To Devon, there was a time when we were close, but that time has passed," Mr Bickford allegedly wrote. "You have joined the ranks of my enemy. And for that I can give you no kind words — return to Allah."

Sources speaking to the New York Post allegedly claimed that Mr Bickford became "radicalised" in recent months, though it is unclear what drove his reported conversion and zealotry.

Mr Bickford was reportedly added to the FBI’s "Guardian Watchlist" after allegedly posting online about his desires to travel to Afghanistan and fight alongside Islamic militants.

A police source speaking to The New York Daily News said the case is being investigated as a terrorist attack.

“It’s being investigated as a terror attack, 100%,” the source told the outlet. “He radicalized about a month ago. He’s not affiliated with any group. It’s more like a lone-wolf situation.”