A violent psych patient in NYPD custody chomped off a security guard’s middle finger at a Brooklyn Hospital, according to court papers.

The unhinged patient, Dmitry Walker, kicked, punched, and bit off security guard Neville Codner’s finger at Brookdale Hospital in Brownsville after officers uncuffed Walker while transferring him from the ER to the psychiatric unit on July 24, 2022, according to a Brooklyn Supreme Court lawsuit Codner filed against the NYPD.

Codner, 60, blamed cops for his gruesome injury, claiming they negligently removed Walker’s restraints before it was safe to do so.

He also accused police of failing to follow protocol and not properly watching Walker after he was admitted to the psychiatric emergency room.

Codner is suing for undisclosed damages.

The NYPD didn’t say why Walker was transported to Brookdale Hospital.

Neither Codner nor his attorney responded to requests for comment.