An ex-con has been nabbed for two knife attacks along the No. 7 subway line in Queens, police said Sunday.

NYPD commish says ‘we keep arresting him’

A Queens man has been arrested for two separate random slashings on a No. 7 train in as many days — including one that left the subway car so bloody, it had to be taken out of service, cops and sources said Sunday.

Donny Ubiera, 32, stabbed two men — one in the face and the other in the neck — without provocation in separate incidents Friday and Saturday morning along the Flushing-to-Midtown subway line, the NYPD said in a statement.

The first attack occurred at 8:40 a.m. during the Friday morning rush hour at Queensboro Plaza in Long Island City, Queens, and left the 62-year-old victim with cuts to the face and hand, according to police.

There was so much blood in the train car that it had to be taken out of service, sources said.

The victim needed stitches to close his wounds.

Ubiera then allegedly struck again the next day at 7:15 a.m. at the 74th Street-Broadway station in Jackson Heights, Queens. Cops said he approached his unsuspecting victim, displayed a “large” knife and stabbed the man in the neck and fled.

The 26-year-old victim told police he was sitting in the train when Ubiera dropped a knife on the floor in front of him, then picked it up, mumbled something and slashed him in the face and arm, then ran off, cops said.

The victim told investigators he’d never seen the attacker before and didn’t interact with him before the slashing.

On Saturday, Ubiera allegedly struck again, stabbing a 55-year-old man in the neck with a kitchen knife as he sat on a bench waiting for the train at the 74th St.-Broadway station about 7:15 a.m., police said. Police recovered the knife in the station; the victim was rushed to Elmhurst Hospital Center is expected to recover.

𝑈𝑏𝑖𝑒𝑟𝑎 ℎ𝑎𝑠 𝑠𝑒𝑟𝑣𝑒𝑑 𝑡𝑤𝑜 𝑝𝑟𝑖𝑠𝑜𝑛 𝑠𝑡𝑖𝑛𝑡𝑠 𝑓𝑜𝑟 𝑎𝑡𝑡𝑒𝑚𝑝𝑡𝑒𝑑 𝑑𝑟𝑢𝑔 𝑝𝑜𝑠𝑠𝑒𝑠𝑠𝑖𝑜𝑛 𝑎𝑛𝑑 𝑑𝑟𝑖𝑣𝑖𝑛𝑔 𝑤ℎ𝑖𝑙𝑒 𝑖𝑚𝑝𝑎𝑖𝑟𝑒𝑑 𝑏𝑦 𝑑𝑟𝑢𝑔𝑠.

𝐻𝑒 𝑐𝑜𝑚𝑝𝑙𝑒𝑡𝑒𝑑 ℎ𝑖𝑠 𝑝𝑎𝑟𝑜𝑙𝑒 𝑆𝑒𝑝𝑡. 21, 𝑝𝑢𝑏𝑙𝑖𝑐 𝑟𝑒𝑐𝑜𝑟𝑑𝑠 𝑠ℎ𝑜𝑤.

𝐻𝑒 𝑤𝑎𝑠 𝑎𝑟𝑟𝑒𝑠𝑡𝑒𝑑 𝑜𝑛 𝑟𝑜𝑏𝑏𝑒𝑟𝑦 𝑐ℎ𝑎𝑟𝑔𝑒𝑠 𝑙𝑒𝑠𝑠 𝑡ℎ𝑎𝑛 𝑓𝑜𝑢𝑟 𝑚𝑜𝑛𝑡ℎ𝑠 𝑙𝑎𝑡𝑒𝑟, 𝑜𝑛 𝐽𝑎𝑛. 10, 𝑎𝑐𝑐𝑢𝑠𝑒𝑑 𝑜𝑓 𝑠𝑡𝑒𝑎𝑙𝑖𝑛𝑔 𝑏𝑒𝑒𝑟 𝑓𝑟𝑜𝑚 𝑎 𝑏𝑜𝑑𝑒𝑔𝑎 𝑖𝑛 𝐸𝑙𝑚ℎ𝑢𝑟𝑠𝑡, 𝑡ℎ𝑒𝑛 𝑓𝑙𝑎𝑠ℎ𝑖𝑛𝑔 𝑎 𝑚𝑒𝑎𝑡 𝑐𝑙𝑒𝑎𝑣𝑒𝑟 𝑎𝑡 𝑎𝑛 𝑒𝑚𝑝𝑙𝑜𝑦𝑒𝑒 𝑤ℎ𝑜 𝑐𝑜𝑛𝑓𝑟𝑜𝑛𝑡𝑒𝑑 ℎ𝑖𝑚.

City Correction Department records show he was released from Rikers Island on May 23. The disposition of the robbery case wasn’t immediately available Sunday afternoon.

On Sunday, NYPD Commissioner Keechant Sewell commented on Ubiera’s criminal background.

“We have arrested a suspect in two slashings on the subway this weekend. Your police are doing their job. We keep arresting him,” she said. “His record demonstrates that each time he is involved in unprovoked violence against innocent victims the criminal justice system has him back to the streets and the subways rather than jail or psychiatric treatment. He inevitably targets another victim. This is nothing if not predictable.”