New York (CNN) -- A New York man arrested in connection with the stabbing of two children in Brooklyn may be linked to another stabbing in a Manhattan subway, a law enforcement official told CNN Thursday. 

Police believe Daniel St. Hubert, 27, was out on parole when he stabbed two young children inside an elevator -- killing one of them. 

St. Hubert was arrested by detectives around 8 p.m. Wednesday. 

He was arrested around the same time that Chief of Detectives Robert Boyce identified St. Hubert by name for the first time as the suspect in the attack. 

Detectives were obtaining evidence Thursday that could link him to a fatal stabbing on the subway in the Chelsea neighborhood of Manhattan, the official said. 

Investigators were executing search warrants to see if he is linked to additional stabbings since his release from prison on May 23, a law enforcement official said. 

Law enforcement has been involved with St. Hubert plenty in the past, including nine arrests, though police did not specify all the outcomes. 

The most recent instance was May 23, when, Boyce said. St. Hubert was released on parole in connection to a domestic assault case. 

Nine days later, police believe he encountered 6-year-old Prince Joshua "PJ" Avitto and 7-year-old Mikayla Capers inside an elevator at a public housing complex in Brooklyn. Mayor Bill de Blasio said the two children were "on their way to get ice cream" at the time. 

For reasons authorities haven't yet explained, the two children were stabbed -- both in the torso. PJ Avitto was transported to a nearby hospital, where he was pronounced dead.  QUESTIONS:

Q1:
1. What was the name of the person who got arrested?
2. Who was detained?
3. Who got taken into custody?
Q2:
1. When was Daniel St. Hubert arrested?
2. When did Daniel St. Hubert get taken into custody?
3. At what point was Daniel St. Hubert detained by police?
Q3:
1. Had Daniel St. Hubert been in prison earlier?
2. Had Daniel St. Hubert already spent time in prison?
3. Prior to his arrest, had Daniel St. Hubert been in prison before?
Q4:
1. Before when had Daniel St. Hubert been in prison?
2. When had Daniel St. Hubert been released from his previous stay of prison?
3. When did Daniel St. Hubert get out of prison prior to his arrest?
Q5:
1. How many times had Daniel St. Hubert been arrested?
2. How many arrests did Daniel St. Hubert have under his belt?
3. What was the number of times that Daniel St. Hubert had been detained?
Q6:
1. What is Robert Boyce's job?
2. How is Robert Boyce employed?
3. What does Robert Boyce do for a living?
Q7:
1. What did Robert Boyce identify?
2. Whose identity did Robert Boyce confirm?
3. What did Roberty Boyce perform identificaiton of?
Q8:
1. What did Robert Boyce identify Daniel St. Hubert for?
2. What was Daniel St. Hubert's identity given for?
3. 
Q9:
1. Why did Robert Boyce identify Daniel St. Hubert?
2. What was Robert Boyce identifying Daniel St. Hubert for?
3. For what reason did Robert Boyce confirm Daniel St. Hubert's identity?
Q10:
1. What was Daniel St. Hubert suspected of doing?
2. What crime was Daniel St. Hubert believed to have committed?
3. What criminal activity was Daniel St. Hubert suspected of being involved in?
Q11:
1. What are the names of Daniel St. Hubert's victims?
2. Who did Daniel St. Hubert stab?
3. Who were the victims of Daniel St. Hubert's attack?
Q12:
1. What was Prince's age?
2. How old was Daniel St. Hubert's male victim?
3. How old was the boy that Daniel St. Hubert stabbed?
Q13:
1. What was Mikayla's age?
2. How old was Mikayla?
3. What was the age of Daniel St. Hubert's female victime?
Q14:
1. Where were Prince Joshua and Mikayla Capers stabbed?
2. What was the location of Prince Joshua and Mikayla Capers's stabbing?
3. Where were Prince Joshua and Mikayla Capers killed?
