NEW YORK (CBSNewYork) – A man in custody in connection with an elevator stabbing in Brooklyn that killed a 6-year-old boy and critically injured a 7-year-old girl is also being eyed in two other knife attacks in the city.
Daniel St. Hubert, 27, was wanted for killing Prince Joshua "P.J." Avitto and critically injuring Mikayla Capers at the Boulevard Houses in East New York on Sunday.
Now investigators say St. Hubert may be connected to a subway stabbing attack Wednesday in Chelsea. In that incident, a man was stabbed multiple times on the southbound No. 1 train platform at 18th Street, police said.
Police spokesman Stephen Davis said St. Hubert was seen on surveillance video near the subway station where the attack occurred. Witnesses said a man who looks like St. Hubert was also seen on the subway platform, Davis said.
In that attack, sources told CBS 2 the victim, a 52-year-old homeless man, was sleeping on the platform and St. Hubert was sitting on a bench. St Hubert then got on an incoming train, quickly jumped off and sat on the same bench.
A witness then heard grunting, turned back around and saw St. Hubert walking away holding a brown knife with an 8 to 10 inch handle, sources told CBS 2.
The witness said the homeless man then yelled, "he just stabbed me," staggered out of the station and collapsed on 7th Avenue and 18th Street, sources said.
The victim is listed in stable condition at Bellevue Hospital.
Police said they are also investigating whether St. Hubert may have stabbed to death 18-year-oldTanaya Copeland, who was killed Friday just a few blocks away from Sunday's incident.
A similar knife was found at the scene of Copeland's slaying, but more forensic & DNA testing is needed, police said.
Listen: Brooklyn Elevator Stabbing Suspect Eyed In Subway Attack, Death Of Teen Girl
St. Hubert was picked up in Queens just after 8 p.m. Wednesday. Sources told CBS 2 police tracked his cellphone and zeroed in on his location.
Davis said it appears St. Hubert had been given a summons Tuesday for public urination in Brooklyn, but that he hadn't yet been identified as the suspect in Sunday's stabbings.
His arrest Wednesday happened less than an hour after Police Commissioner Bill Bratton and Mayor Bill de Blasio named St. Hubert as a suspect and turned to the public for help in finding him.
"I want to thank everybody who has been involved in this whole ordeal from start to finish," P.J.'s mother, Aricka McClinton, said Thursday morning. "You all didn't rest, you didn't eat, you didn't sleep. You did what you had to do."
P.J.'s father, Nicholas Avitto, said he would ask the suspect a few questions if he saw him.
"Why would you do this?" he said. "What compelled you to do this?"
Around 6 p.m. Sunday, the children had been playing outside under adult supervision when they went upstairs to get some ice cream from P.J.'s sixth-floor apartment.
That was when police said the suspect followed them into the elevator and used a steak knife to stab each child multiple times.
P.J. died at a hospital. Mikayla remains in critical but stable condition. Her family says she is in the Intensive Care Unit with a breathing tube and is in and out of consciousness, but responding to commands.
Investigators said St. Hubert had shaved his head since Sunday's stabbing. He was on parole and had missed a scheduled meeting with a parole officer on Tuesday.
Police said they were able to identify St. Hubert as a suspect from DNA found on the knife used in the elevator attack.
Investigators say St. Hubert had been let out of prison on May 23 after serving a five-year sentence for domestic assault and attempted murder for trying to kill his ex-girlfriend.
He also has nine prior arrests, including two for assaulting police and correction officers.
Back in 2008, his own mother filed an order of protection against him. Months later, police said he punched her numerous times in the face, wrapped an electrical cord around her head and told her he was going to kill her.
He was eventually sent to a psychiatric facility for seven months.