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 have n'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 . `` These parents are in such pain now , '' de Blasio said . `` ... I ask all New Yorkers to help in this investigation any way you can . Do it for this grieving family . Do it for all of us . '' Police initially said Mikayla was in critical condition . Speaking Wednesday about her current state , the mayor said , `` She 's doing much better . She 's a strong young lady . '' A knife believed to have been used in the attacks was recovered at the scene . A law enforcement official said Wednesday that DNA evidence from that knife helped police identify the suspect . Police Commissioner Bill Bratton , however , added later in the day that police `` said nothing about DNA '' while insisting forensic evidence more generally helped lead them to the suspect . As the investigation continues , families of the two stabbed children struggled with the senselessness of the attack . `` Pray for her , and us . And pray for PJ 's family . This is senseless . I do n't know what monster would do something like this , '' said Regenia Trevathan , the girl 's great-grandmother , to CNN affiliate WCBS . Scott Avitto , PJ 's uncle , similarly said the violence `` does n't make any sense . '' `` We 're all just struggling , we 're trying to pull it together , '' he added . `` Our family is strong , but we just want justice to be done . '' Avitto was related to Taj Gibson , a forward for the Chicago Bulls . Gibson tweeted Monday morning : `` They killed my lil super man . # rippj only two more weeks until your 7 birthday . Tears forever . '' Gibson also posted a picture of Avitto to his Instagram account . PJ 's godfather , Henry Alston , said the boy 's funeral will be Friday . Investigators are considering the possibility the suspect may be responsible for another fatal stabbing that occurred just two days earlier and blocks away . Tanaya Copeland , 18 , was found in the same neighborhood Friday night , unconscious and unresponsive with multiple stab wounds to her torso . Copeland was pronounced dead at a nearby hospital , police said . The close proximity of the incidents , as well as similarities in the type of weapons used , have led detectives to believe the two cases may be related . `` We have to proceed as if they are aligned , '' Boyce said . `` The knives are very similar . The proximity is four blocks . We have a basic description of the male . '' 12-year-old girls accused of stabbing friend . CNN 's Kevin Conlon , Ray Sanchez , Adam Reiss and Shimon Prokupecz contributed to this report .
NEW : Authorities apprehend suspect in stabbing , 27-year-old Daniel St. Hubert . The man was taken to a hospital for treatment of his injuries. Police say St. Hubert was out on parole tied to domestic assault since May 23 . NEW : Mayor says injured 7-year-old girl `` is doing much better '' Prince Joshua `` PJ '' Avitto , 6 , was killed in the stabbing .