The gunman caught on video opening fire inside the emergency room of a New York City hospital has been taken into custody after police discovered he wrote his name in the facility’s sign-in book, reports say. 

Keber Martinez, 25, of the Bronx, now faces attempted murder, reckless endangerment and criminal possession of a firearm charges stemming from the shooting that unfolded Tuesday at Jacobi Medical Center, according to the New York Police Department. 

Police told Fox5 NY that Martinez wrote his name in the Bronx hospital’s sign-in book, making it easier for investigators to track him down. He was arrested late Tuesday night. 

The shooting was caught on hospital surveillance cameras.

NYC HOSPITAL SHOOTING CAUGHT ON VIDEO 

In a statement, the NYPD said they responded to the hospital midday Tuesday after receiving a 911 call about a person being shot inside there. 

"Upon arrival Police discovered a 35-year-old male with a gunshot wound to the arm," the statement read. "The victim was immediately treated by medical personnel on location." 

Police say Martinez got into a verbal dispute with the victim before discharging "several rounds." 

The victim, who has not been identified, is expected to survive. He and Martinez also are believed to have known each other, according to ABC7

The shooting happened at the Jacobi Medical Center in New York City's Bronx borough. (Google Maps)

The entire incident was captured on hospital surveillance cameras, showing calm in the waiting room before the gunfire erupted. 

"This was a cowardly act in a space where New Yorkers come for healing and care. Our health care heroes swiftly took care of the shooting victim and took actions to protect the other patients in the waiting room," the hospital said in a statement after the shooting. "Our immediate focus is on caring for the patient and ensuring the safety of our staff. We are working closely with the NYPD as they conduct their investigation." 

Martinez is familiar to police as he has had six prior arrests, the most recent being in May 2020 for charges of assault, drugs, grand larceny and criminal possession of a weapon, ABC7 reported. 

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"Today’s shooting is a sad reminder that we need to address the devastating problem of gun violence in our communities," Bronx Borough President Vanessa Gibson tweeted. 

"My residents and families of the #Bronx deserve to be safe just as anyone else. It’s unacceptable that children are shot in car seats with their parents and patients shot waiting in emergency rooms. This is madness! Out of control. We are in a State of Emergency," she added. 

Fox News’ Lawrence Richard contributed to this report.